Nobel Peace Prize winner Jose Ramos-Horta was sworn in as East Timor's new prime minister Monday, pledging to end the violence that has wracked Asia's newest nation and sent 150,000 people fleeing their homes.

He also criticized the United Nations, saying the world body left before the traumatized country was on its feet. The United Nations administered East Timor for two years after its bloody break from Indonesian rule in 1999.

"Is it possible to build a state in two years? The answer is no, but the Security Council had other concerns and priorities," Ramos-Horta said in his address. "And we, the Timorese, fueled by patriotism, even thought that a transition of two years was excessively long."

Ramos-Horta replaced Mari Alkatiri, who resigned last month after failing to stop the violence that erupted in the capital when he dismissed 600 soldiers — more than 40 percent of the country's army — after they went on strike complaining of discrimination.

The dismissal set off fighting between the security forces that later spilled over into gang warfare, looting and arson that left 30 people dead and sent 150,000 into tent camps.

"Our immediate task is to consolidate the security in Dili and in all of East Timor," Ramos-Horta said. "The government must take action in the weeks and months ahead to restore faith and hope."

A mob on Sunday chased a man through Dili's streets and into a hotel, badly beating him with gunbarrels and sticks. The circumstances of the beating were not clear, but it highlighted the still-fragile security situation.

In recent weeks Ramos-Horta has joined calls for the resignation of Alkatiri, who also faces allegations of forming a hit squad to kill his opponents during the unrest. But on Monday the new prime minister had only kind words for his predecessor and said he would seek Alkatri's advice on governing the country.

East Timor remains desperately poor seven years after it voted to break from 24 years of Indonesian rule in a U.N.-sponsored ballot.

Ramos-Horta, who won the Nobel prize in 1996 for his nonviolent resistance to the Indonesian occupation during his years spent in exile, is popular among the international community and is close to President Xanana Gusmao.

But it remains to be seen how well he will work with the ruling party, Fretilin, which is still headed by Alkatiri and holds 55 of 88 seats in parliament.

Alkatiri has been summoned by prosecutors investigating the hit squad claims but denies any wrongdoing, and on several occasions described the events leading to his downfall as a coup.

The recent violence was the worst to hit the country since 1999. Though it eased with the arrival of 2,700 foreign peacekeepers six weeks ago, isolated incidents still occur.

The United Nations said it expects peacekeepers to stay on in the country for several years.