Nobel peace laureate Jose Ramos-Horta, East Timor's newly elected president, took the oath of office at a simple ceremony in Dili yesterday, as fresh violence erupted in the troubled country.

Ramos-Horta, who spent years abroad as a spokesman for East Timor's struggle for independence from Indonesian occupation, succeeds Xanana Gusmao after winning nearly 70 percent of the votes in a May 9 election run-off.

His victory has raised hopes of greater stability in a nation still struggling to heal divisions five years after it won independence from Indonesia.

Ramos-Horta, 57, vowed to guarantee East Timor's stability at the swearing-in, held at the heavily guarded national parliament building. The two-hour ceremony was attended by parliament members, diplomats and Indonesian Foreign Minister Hassan Wirajuda.

"I will ... obey the constitution to guarantee national unity and the stability of the nation," said Ramos-Horta, dressed in a formal jacket.

"As a new president ... I will follow the steps of outgoing president Xanana Gusmao to realize peoples' dreams ... I will find a way to end the crisis in the country."

In a speech delivered in four languages - East Timor's national language Tetum, Portuguese, English and Indonesian - Ramos-Horta urged street gangs to end all violence "because it just destroys the nation."

But hours after he was sworn in, one person was killed and two were injured in a clash between street gangs throwing rocks at each other, police said. Police also arrested more than 40 people in connection with the violence.

Violence erupts sporadically in East Timor, but the run-off between Ramos-Horta and parliament chief Francisco Guterres, president of the Fretilin party, was peaceful.

Clashes between gangs and martial arts groups have erupted recently.