PODGORICA, Yugoslavia (AP) _ The Yugoslav army today disputed the Montenegrin government's allegation that its soldiers killed ethnic Albanian refugees in northern villages this week, contending they were Kosovo rebel fighters.

The killings, and the refusal by the pro-Western government of President Milo Djukanovic to put its police force under army command, are further straining relations between the republic's leadership and the military, commanded from Belgrade.

The republic of Montenegro and the much larger Serbia make up Yugoslavia.

Djukanovic is at odds with the Yugoslav President Slobodan Milosevic, and Western leaders fear Milosevic is plotting a military coup to take control of Montenegro.

``Britain and NATO remain vigilant and gravely concerned,'' British Defense Secretary George Robertson said today.

Milosevic has already appointed his loyalists to head army troops in Montenegro, which with a recent mobilization have expanded to about 24,000. The 10,000-strong police force is controlled by Djukanovic.

``It is out of the question that the ministry of the interior could be subordinated to the Yugoslav army,'' Britain's Financial Times quoted Djukanovic as saying. ``Such an idea is unacceptable.''

Montenegro vice premier, Dragisa Burzan, told reporters late Tuesday that the government has not even discussed the army demand.

``We stick to our earlier decision not to put police on disposal or under control of the army, so we did not even have to discuss that,'' Burzan said.

Burzan toured northern Montenegro villages on Tuesday that Yugoslav army reservists and paramilitary units occupied for two days, expelling villagers and reportedly killing six of them. U.S. Defense Department officials said Serbian forces had begun driving ethnic Albanians out of Montenegro.

``It is a crime against humanity, and whoever committed it must be tried in The Hague,'' Netherlands, where the international war crimes tribunal is based, Burzan said.

He said the police investigation showed the six were Albanian refugees who found shelter in the villages after being expelled from Kosovo.

But the Yugoslav military command in Montenegro claimed in a statement published today that the killed were Kosovo Albanian rebels, who infiltrated into northern Montenegro villages. The army said it killed four ``terrorists'' in the battle.

The troops withdrew from the villages late Tuesday.