The National Liberation Army (Albanian: Ushtria Çlirimtare Kombëtare - UÇK; Macedonian: Ослободителна народна армија - ОНА), also known as the Macedonian UÇK, was a militant organization that operated in the Republic of Macedonia in 2001 and was closely associated with the KLA.
Following the 2001 Macedonian War, it was disarmed under the terms of the Ohrid Agreement, under which greater rights and autonomy were to be given to the country's Albanian minority population. However, in the disarmament of the organization, mainly outdated weapons were returned.
The NLA was founded in the fall of 1999, and was led by former KLA Commander Ali Ahmeti, nephew of one of the founders of the KLA, but was out of the public eye until it began to openly engage the Macedonian military and police. The NLA's proclaimed goal was equal rights for the ethnic Albanian minority within a confederate Macedonia. Senior NLA commanders insisted that "We do not want to endanger the stability and the territorial integrity of Macedonia, but we will fight a guerrilla war until we have won our basic rights, until we are accepted as an equal people inside Macedonia."  The Macedonian government claimed the NLA were an extremist terrorist organization seeking to separate Albanian majority areas and unite those territories with Albania.
Beginning on January 22, 2001 the NLA began to carry out attacks on Macedonian security forces, using light weapons. The conflict soon escalated and by the start of March 2001, the NLA had taken effective control of a large swathe of northern and western Macedonia and came within 12 miles of the capital Skopje.
In March 2001, NLA members failed to take the city of Tetovo in an open attack, but controlled the hills and mountains between Tetovo and Kosovo. On May 3, 2001 a Macedonian government counter offensive failed in the Kumanovo area. By June 8, the rebels took Aračinovo, a village outside of Skopje. On August 16, the two sides signed a peace deal ending the open conflict.
The NLA was estimated to comprise around 5,000 - 7,000 men at its peak and some of its members were trained by British SAS and Parachute Regiment officers. As was the case with the KLA, they were fairly lightly armed - generally with small arms and mortars - though there were later reports that they had acquired FIM-92 Stinger and SAM-7 anti-aircraft missiles. As the war progressed the rebels managed to acquire heavy weapons including T-55 tank's and armoured personnel carriers captured from Macedonian government forces.
Although the conflict in Macedonia was brief, it was not scant of war crimes. According to Human Rights Watch, "Ethnic Albanian rebels in Macedonia tortured, sexually abused road workers after abducting them from the Skopje-Tetovo highway..
Dozens of ethnic Macedonians were kidnapped. While many were released after a short time, 12 people apparently remained missing after the NLA released 14 others in late September. In October, reports suggested that the 12 may have been killed and buried in mass graves near Neproshteno. The case was referred by the Macedonian government to the International Criminal Tribunal for the former Yugoslavia for investigation.
Another incident which is claimed by Macedonian government to be a war crime was that of the so-called Vejce massacre where Albanian guerrillas ambushed and killed 8 Macedonian special forces from the Lions unit. Where allegedly the victims were executed with cold steel weapons.A patrol of 16 special operatives were coming back from a raid in a nearby village which they had raided a few hours earlier they looted and beat the villagers is what they said, this was done several times a week through 5 villages the patrol rout was always the same which the investigation after the massacre claimed that Albanian guerrillas had been monitoring the patrol for some weeks after they got complains by the ethnic Albanian villagers and had realised that the patrol was always the same rout and approximate times. The families of the dead soldiers and several ministers claim that the information was sold to the guerrillas and that a major betrayal took place. After setting up and ambush and attacking their lightly armoured Humvee vehicles with small arms fire and RPG’s the patrol stopped and Macedonian forces and guerrillas exchanged fire in a short skirmish, after soldiers started retreating half of the patrol managed to escape one soldier was shot and 7 others captured and allegedly executed which knifes and then their corpses were allegedly burned.News of the massacre sparked local uprisings against Muslim Albanians in several towns and cities across Macedonia, and such revolts included burning and vandalising shops and Mosques. Surviving members of the roadside patrol that was massacred gave eyewitness testimony of the killings. They claimed that the massacre was carried out by a group of 10 bearded men. Till this day the bodies were not released to the public or civilian investigators and autopsies were carried out in a military morgue.
The alleged NLA bombing of the 13th-century Orthodox monastery Sveti Atanasij in the village of Lesok however no one has ever claimed responsibility for the attack and Albanian guerrilla officials have demised all responsibility and placed the blame on Macedonian special forces saying it was another poor attempt to link the NLA to Islamic extremism, like that of the Asian immigrant massacre and that these incidents were seriously putting the Ohrid agreement and the established peace treaty into jeopardy. Eye whiteness interviewed by British Telegraph reported claimed the cooperates of this incident came from the ethnic Macedonian village of Rate. Even the Macedonian ministers and diplomats in Skopje agreed that the possibility of this attacking being carried out by Albanians was unlikely as the NLA had no history of attacking any religious or cultural buildings or sites. NATO Military experts said that by evidence gathered from “The fact that the battery was lying within an area spattered by rubble and wreckage seemed to suggest that it was detonated using a relatively sophisticated timer device“ also the extensive amount of explosive used and the type of explosive all pointed to the Macedonian military. This incident is to this day disputed and the monastery is now under reconstruction built with some donations from the Albanian Islamic Union of Macedonia to erase any bad blood and Macedonian government. On the other hand, the Macedonian forces blew up a mosque in the town of Neprosteno. Both structures were rebuilt in 2003 with funding from the EU. The most notable incident was the infamous Asian Immigrant Massacre, when Macedonian special police forces murdered six Pakistanis and an Indian immigrants afterwards planting weapons, explosive and Islamic literature on the corpses calming they were Al-Qaida cells which were about to attack US Embassy in Skopje. This was conspired by Macedonian government to link the Albanian guerrillas to Al-Qaida so that Macedonia can sympathise with the west by making it seem they are to fighting a War on Terror against Islamic extremists. This atrocious war crime was heavily criticised by the whole world and caused Macedonia to lose much of its foreign support especially from the west, the EU and Pakistan governments strongly insisted that the people responsible for this war crime be brought to justice but the four men allegedly responsible for this were cleared of all charges and received a hero’s sheared after they left court. There were disturbing images of the dead bodies released to parade the victims on TV as trophies.  
Other crimes were like that of a three-day operation by Macedonian police against the ethnic Albanian village of Ljuboten, from August 10-12, 2001, which left ten civilians dead and resulted in the arrest of more than 100 men, many of whom were severely beaten and tortured while in police custody. According to the Macedonian government there was a presence of Albanian National Liberation Army in the village; however, the Human Rights Watch investigation on the ground in Ljuboten found no evidence of this and said it was a clear violation by Macedonian forces on human rights. These events led to the trial of the Macedonian minister of internal affairs of the time, Ljube Boškoski, in the International War Crime Tribunal in The Hague.. Eventually he was found not guilty.
After the Ohrid Agreement, the NLA agreed to cease-fire in June. Under the Ohrid Agreement, the Macedonian government pledged to improve the rights of the Albanian population, that make up just over 25 % of the population. Those rights include making Albanian language an unofficial language, increasing the participation of ethnic Albanians in government institutions, police and army. Most importantly, under the Ohrid Agreement, the Macedonian government agreed to a new model of decentralization.
The Albanian side agreed to give up any separatist demands and to fully recognise all Macedonian institutions. In addition, according to this accord the NLA was to disarm and hand over their weapons to a NATO force.
Operation "Essential Harvest" was officially launched on 22 August and effectively started on 27 August. This 30-day mission was to initially involve approximately 3,500 NATO that number went up to 4,200 NATO troops and Macedonian troops to disarm the NLA and destroy their weapons. Just hours after NATO wrapped up the operation, Ali Ahmeti told reporters attending a news conference in the rebel stronghold of Sipkovica that he was dissolving the National Liberation Army and that it was time for ethnic reconciliation.
Many members of the Albanian NLA, led by Ali Ahmeti, later formed the Democratic Union for Integration, a political party that won the majority of the Albanian votes in the 2002 election and formed part of the ruling coalition along with SDSM and LDP until August 2006 when, following July 2006 parliamentary elections, a conservative VMRO-DPMNE / DPA coalition came to government . Total casualties of war on each side are not known, but both sides claimed their own military casualties were around 60 each, while about 60 - 80 ethnic Albanian civilians and possibly about ten Macedonian civilians are thought to have been killed. (See Casualties and displacement in the 2001 Macedonia conflict)