Scores of homes have been burnt in two districts in East Timor, amid protests triggered by the appointment of a new prime minister.
There has been sporadic violence since Mr Gusmao was named PM
The worst violence was in Viqueque and Baucau in the east, both strongholds of former ruling party Fretilin.
Gangs of youths torched buildings, forcing people to flee, reports said.
Fretilin won the most seats in polls in June, but was excluded from government after Xanana Gusmao formed a majority coalition and was named prime minister.
Mr Gusmao, an independence hero who has also served as president, was appointed by the president on Monday and sworn into office on Wednesday.
There have been outbreaks of violence all week, mainly in the capital, Dili as well as in Viqueque and Baucau.
According to the UN Mission in East Timor, a total of 142 houses had been burned in the two eastern districts.
But other reports suggested the total was higher.
A police commander in Viqueque, Jose de Carvalho, told Reuters news agency that gangs had torched 200 houses in the district, forcing about 1,000 villagers to flee to the mountains.
"Based on our observation, they don't have clean water and food to eat, and no government officials are coming," he told the agency.
Foreign troops had calmed the situation, he said. International peacekeepers have been in East Timor since violence last year left more than 30 people dead.
President Jose Ramos-Horta has condemned the violence.
"The latest developments in Dili, Baucau and Viqueque have brought grief to the people," he said on Thursday.
Mr Gusmao has formed a coalition with smaller parties
"The violence is proof that these Fretilin elements have no understanding or adequate knowledge of their party's participation in this country's democratic institutions."
The unrest follows polls in June in which neither Fretilin nor Mr Gusmao's CNRT party were able to achieve an overall majority.
Fretilin won 21 seats and argued that it should form the government because it got the most votes.
But the CNRT, which won 18 seats, gained a parliamentary majority by forming an alliance with smaller parties.
Weeks of negotiations on forming a unity government brought no result, so on Monday Mr Ramos-Horta used his constitutional right to appoint a prime minister.
Fretilin has denounced the move and says it plans to challenge the decision.