Updated

The U.N. Security Council (search) voted unanimously Sunday night to authorize the immediate deployment of an international military force to Haiti (search) for three months to restore order.

The vote came minutes after the Pentagon announced that U.S. Marines (search) had arrived in Haiti as the vanguard of an international security force. The Marines are expected to be joined in the coming days by soldiers from France, Canada and several Caribbean nations.

The resolution states that "the situation in Haiti constitutes a threat to international peace and security and to stability in the Caribbean, especially through the potential outflow of people to other states in the subregion."

It authorizes "a multinational interim force" to remain in the lawless Caribbean nation for "not more than three months" to help restore stability and security and to support "the constitutional political process underway in Haiti." The Security Council will then be prepared to establish a U.N. peacekeeping force to remain in Haiti for a longer, unspecified period, it says.

France's U.N. Ambassador Jean-Marc de La Sabliere praised the council for its "swift response to an urgent need."

"This force will contribute to restore and secure a stable environment in Haiti," he said.

The council received a letter from Haiti's Chief Justice Boniface Alexandre, who replaced President Jean-Bertrand Aristide (search) on Sunday morning after he fled the country, requesting an international force, said China's U.N. Ambassador Wang Guangya, the current council president.

The United States and France refused on Thursday to support the immediate deployment of a multinational force, insisting that there had to be a political settlement in Haiti first. With Aristide's departure, the two countries — who were at odds during the Iraq war — jointly called for Sunday's emergency council meeting to get military troops into Haiti as quickly as possible.

The force would also facilitate the provision of humanitarian aid and international assistance to the Haitian police "in order to establish and maintain public safety and law and order and to promote and protect human rights," according to the resolution.

U.N. Secretary-General Kofi Annan (search), who was in the Security Council chamber for the vote, said later that it sent a signal to the Haitian people "that the international community has not forgotten them."

"We understand their need and we are standing by them in their hour of need," he said. "The international community will do whatever it can to help stabilize the situation. I know some of them may think it's a bit late, but it's always ... better late than never, and we will do what we can to support them."

The vote was delayed because the initial draft resolution called for the international military force to remain in Haiti for just two months.

Annan said that was an unrealistic timetable to deploy a U.N. force, which would require "three to four months." The United Nations has no standing army and must ask the 191 U.N. member states to contribute troops or civilian police to a force.

The council suspended the meeting so a loose grouping called the Friends of Haiti could amend the text. The council then met again and approved the deployment for up to three months.

"We think this is an important step," said U.S. Ambassador John Negroponte. "We think, with the developments of today, Haiti has turned a new page in its history ... and the international community has an opportunity to assist the country ... in getting back on the path toward the establishment of a stable and democratic society."

Annan was asked why Haitians should expect a better outcome now than 10 years ago, when U.S. forces restored Aristide's elected government to power.

"This time," said Annan, "I hope the international community is not going to put a band-aid on, and that we are not only going to help stabilize the current situation, but assist the Haitians over the long haul and really help them pick up the pieces and build a stable country."