Commercial flights were reportedly continuing in and out of the airport, but the U.S. state department urged citizens to make plans to leave and ordered out all non-essential staff.

At their worst, clashes over the past two months have involved gunbattles and widespread arson, sending thousands to seek safety in the hills, or on the grounds of embassies, religious institutions and military installations.

The ostensible reason for the unrest is unhappiness of sacked soldiers over firings, benefits and discrimination.

Officials say opposition groups have exploited the situation, sparking attacks and resisting mediation. Fear and panic have been fanned by rumours spread by handphone text messaging.

East Timor is one of the world's poorest countries but has potentially lucrative oil and gas reserves that could inject up to $14.5 billion into its struggling economy.

It is also strategically placed amidst territory belonging to one-time ruler Indonesia, with Australia its other nearest neighbour.

Australia led a U.N.-backed intervention force in 1999 to quell violence after East Timorese voted for independence. An estimated 1,000 people died in that violence, blamed mostly on pro-Jakarta militia backed by Indonesian military elements.

Despite that rocky history, Indonesia has been trying to improve trade and political ties with Dili since independence.

"We think that the government of Timor Leste knows best about what is happening and what kind of steps that need to be taken," said Desra Percaya, Indonesian foreign affairs spokesman, when asked about the foreign troop deployment.

Malaysia will deploy 275 para-commandos, an army official told Reuters. The group would leave late on Thursday using C-130 Hercules aircraft. They would be part of an eventual total Malaysian force of 500 men, comprising the military and police.

"We have activated a recce team which left at 11 a.m. today, comprising a 25-member advance team," Defence Minister Najib Razak said.

When Indonesia invaded East Timor in 1975, and in 1976 declared it an Indonesian province after centuries of Portuguese control, the U.N. never recognised Jakarta's legitimacy.

That helped encourage a simmering pro-independence rebellion and a U.N. feeling of responsibility for making East Timor a success once it became independent.

The Portuguese government said it would send 120 military police to help in the security effort.