An ethnic-Albanian fighter looks over the Tetovo valley

The group took heavy incoming fire from the Macedonian security forces just inside the border before they made it through to their own lines.

The NLA is using Kosovo as a rear supply base and safe area and many, perhaps most, of its members did fight in Kosovo, in the KLA.

Home-grown movement

While there are some Kosovo-born volunteers in the NLA, almost every member I have spoken to says the group is composed overwhelmingly of Macedonian-born Albanians.

We will fight a guerrilla war ... until we are accepted as an equal people inside Macedonia

NLA senior commander

They say they are returning to their homeland to fight a long-planned-for "war of liberation".

One of the senior commanders, himself a veteran of the KLA, blamed the situation on "a decade of oppression by the Slav Macedonian government.

"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."

Macedonia is not Kosovo.

Many ethnic Albanians in Macedonia complain of human rights abuses by the police, but, unlike in Kosovo, there have been no massacres by the security forces.

Macedonia also has a multi-ethnic coalition government in which the biggest ethnic Albanian political party is the junior partner.

It has always represented itself as a model of how different peoples could live together in peace.

These actions are designed to get the attention of the police and the government ... to make them sit down and talk

NLA senior commander

I asked the senior NLA commander how he could justify killing policemen when there appeared to be political means of advancing the rights of his people.

He replied that the Albanians in the Macedonian Government were more concerned about keeping their well-paid jobs and exercising lucrative patronage than in the national interest of their people.

"These actions are designed to get the attention of the police and the government in Macedonia, to make them sit down and talk and solve the problem peacefully."

Ethnic Macedonians being told to leave their home in Lasce, Macedonia,

The commander set out a number of other aims which military action was supposed to achieve: Unbiased international mediation, international peacekeepers, including Americans and a new Macedonian constitution which would give greater autonomy to Albanian areas.

The remark about wishing to preserve the territorial integrity of Macedonia was the first manifestation of a carefully worked-out political strategy designed by the leadership to reassure the international community.

Ordinary fighters, too, know the importance of the propaganda war: They told me they were doing no more than defending their own homes and villages, and there was no talk of Greater Albania, or even of Greater Kosovo.

The lesson of Kosovo

The NLA is acutely aware that the Kosovo Liberation Army became the most successful guerrilla movement of modern times, without winning a single battle.

That is because they managed, with the help of the then president, Slobodan Milosevic, to bring Nato into the war.

The NLA know that the West might support a battle for human rights, but it will not support a battle for territory.

But their strategy has not worked and the NLA's leadership is disappointed that it does not have the support of either the Albanian Government or prominent veterans of the Kosovo conflict such as the former KLA leader, Hasim Thaci.

Growing support

But support for the rebels is growing in neighbouring Kosovo and the international community will have to apply pressure here if it wants to keep the NLA in complete political isolation.

The NLA is now thought to have between 200 and 800 active fighters and, at the NLA headquarters I visited, there seemed to be no shortage of weapons.

More Macedonian troops have been deployed in Tetovo

I went to other villages near Tetovo, expecting to find opinion divided over the NLA, but instead was surprised to find that everyone I asked said they were prepared to fight.

Despite this, it still appears that those who want an armed struggle are a minority within a minority.

But as so often in the Balkans, once the guns come out, nothing can be taken for granted.

The crucial, unanswered, question, remains how much support the NLA can win among ordinary ethnic Albanians.

The answer will determine whether there are simply more sporadic clashes - or if Macedonia slides towards civil war.