Croatia has lodged a protest with the United Nations after accusing Yugoslav troops of entering a demilitarised zone on the Adriatic coastal border between Croatia and the Yugoslav Republic of Montenegro.

At the same time, the Montenegin Government, which is at odds with Belgrade, said the army had closed its border with Croatia.

The demilitarised zone lies in the area of the Prevlaka peninsula, which is claimed by both Zagreb and Belgrade.

Its future was left unsettled at the end of earlier wars during which Croatia and Bosnia broke away from Yugoslavia.

Before that, the peninsula was recognised as part of Croatia, but it controls access to Kotor Bay in Montenegro - the site of an important Yugoslav naval base.

The Croatian Government says between 200 and 300 Yugoslav troops moved into the demilitarised zone, which had been monitored by United Nations observers.

Withdrawal

The Croats do not seem to be alleging that the troops entered Croatian territory, but they are demanding their immediate withdrawal.

A protest to the UN Security Council said the incursion violated an agreement between Croatia and Yugoslavia as well as Security Council resolutions.

The alleged move by Belgrade appears to be linked to its dispute with the government of Montenegro, which has criticised its actions in Kosovo.

Montenegro's border closed

Tensions between the federal Yugoslav army and the Montenegrin authorities have been rising, with Nato repeatedly warning President Milosevic against mounting a coup.

Montenegro said that army troops had closed its border with Croatia after demanding that the local police give up control.

Two crossing points into Croatia were opened only a few months ago.