PODGORICA, Yugoslavia (AP) _ Two Britons and two Canadians have been arrested in the Yugoslav republic of Montenegro for allegedly training the republic's pro-Western forces to commit ``terrorist actions,'' the Yugoslav army announced Thursday.

The arrests stepped up the pressure on the leadership of Montenegro, which has allied itself with the West and drifted away from Yugoslav President Slobodan Milosevic's regime.

The two British detainees are instructors at the police academy run by the Organization for Security and Cooperation in Europe in the Serb province of Kosovo, while the two Canadians work for a private contractor. An OSCE spokeswoman quickly denied the Yugoslav allegations about the four, saying they were simply returning to Kosovo after a brief vacation.

The allegations are ``absolutely absurd,'' said the spokeswoman, Melissa Fleming. But she also said international OSCE staffers in Kosovo were ordered several weeks ago not to travel by land to Montenegro because of the risk of being picked up by the Yugoslav army.

The four were detained late Monday or early Tuesday near the border between Kosovo and Montenegro. A Yugoslav army statement said they were armed ``with military equipment'' and explosives.

``There are indications that the arrested foreigners were training special units of Montenegrin police and that they are specialists for explosives and terrorist actions,'' the statement said. It added that police found ``enough material to prove the true intentions and aims of the arrested.''

However, Yugoslav state television showed only a few cables, a Kosovo map, pocket knives and a pair of pliers supposedly taken from the four.

Meridian Resources, which employed the Canadians in Kosovo, identified them as Shaun Going and his nephew, Liam Hall. OSCE would not release the Britons' names, but the Yugoslav army identified them as Adrian Prangel and John Yore.

The British Foreign Office said it was ``unacceptable to parade British citizens _ policemen seconded to the OSCE as part of the United Nations Mission in Kosovo _ before the world's media accused of terrorism and espionage.''

``No evidence was produced to support these charges,'' the Foreign Office said. ``These policemen are playing a key role in maintaining peace in Kosovo, a role endorsed by the U.N. Security Council.''

The incident comes amid rising tensions throughout Yugoslavia ahead of national and presidential elections set for Sept. 24.

Montenegro has announced it will boycott the balloting. That has raised fears that Milosevic may seek to provoke a crisis and seize control of the republic by force.

Authorities in Serbia, the larger and dominant Yugoslav republic, recently alleged that special British forces and other foreign experts were training Montenegrin police to prepare for its independence from Yugoslavia. Following the announcement of the arrests, Montenegro's ruling Democratic Party of Socialists accused Milosevic of spreading lies to set the stage for a takeover.

``How else can one interpret such an amount of lies and vulgar inventions, then as setting the stage for the elimination of Montenegro and the removal of its democratic government?'' the party said.

On Monday, Yugoslav authorities announced that four Dutchmen were arrested in July for allegedly plotting to assassinate Milosevic. The government also claims NATO has hired mercenaries to kidnap fugitive war crimes suspects hiding in Yugoslavia.

Montenegro has waived visa requirements for foreigners, and the republic's police allow visitors to enter and leave the republic. But the Yugoslav army, loyal to the central government in Belgrade, does not recognize the Montenegrin waiver.