United Nations officials in West Timor have confirmed the arrest of a pro-Indonesian militia leader suspected of involvement in atrocities in East Timor last year.

Moko Soares was picked up on Monday after weeks of discussions between the authorities in West Timor, UN officials and General Peter Cosgrove, head of the UN peacekeeping force Interfet.

Mr Soares is being charged with illegal possession and sale of weapons. He is said to have been found with several rifles and other ammunition when he was detained at his home near the border between West and East Timor.

Indonesian and UN police have agreed to jointly interrogate and fingerprint Mr Soares.

The UN Transitional Administration in East Timor (UNTAET) wants Indonesia to take legal action against him.

"He has been detained in Indonesia, and clearly there is an obligation for him to be tried," UNTAET legal advisor Judge Hans Joerg Strohmeyer said.

Mr Strohmeyer said that should Mr Soares not be tried in Indonesia, then he should be extradited to East Timor for trial.

"But to my knowledge no formal extradition request has been made," Mr Strohmeyer said, responding to reports that such a demand had already been made.

Killing allegations

Moko Soares is alleged to have been involved in the killing of dozens of people in the East Timorese enclave of Oecussi, 500 metres from the border with West Timor, where more than 40 people are reported to have been hacked to death or shot by militiamen, aided by the Indonesian security forces.

Sergio Vieira de Mello, the UN administrator in East Timor, told the Security Council last week that "thugs" arrested in the eastern part of the island recently had been interviewed about Mr Soares.

Mr Soares was reported to have ordered them to kill someone associated with the United Nations to bolster their standing with Indonesian soldiers, Mr Vieira de Mello said.

The militia herded hundreds of thousands of East Timorese over the border to West Timor during the violence which followed the pro-independence vote in the territory last August.

More than 100,000 are still in gang-controlled refugee camps, some of which Secretary-General Kofi Annan will visit next week.

Armed police

United Nations police officers in East Timor are being issued with side arms in a bid to address recent violence.

UN police officers will be permitted to use guns if their life - or that of a third party - is in immediate danger.

Although every officer in the multinational force has been trained to use firearms, each will undergo further testing to make sure they are competent.

The first side arms will be issued to officers at Dili jail, and to patrol officers over the next month.

In other moves aimed at addressing the recent unrest, the force increased patrols of the Dili market and recruited some 200 East Timorese who formerly served with the Indonesian police.

Officers arriving in East Timor this week will increase the civilian force's strength to 600 - it is authorised to number up to 1,640.