The United Nations Security Council voted unanimously late Sunday to approve a multinational military force to restore order in Haiti.

The 15-member body agreed to the plan during an emergency session, saying force is necessary to "contribute to a secure and stable environment" in the region.

• INDEPTH: Haiti

A gunman in Port-au-Prince on Sunday(Photo: Stephen Puddicombe, CBC Radio News)

After weeks of increasing pressure to resign, Haiti's President Jean-Bertrand Aristide fled the country Sunday morning as armed rebels neared the capital city.

• RELATED: Aristide leaves office, flees Haiti

The U.S. flew a few hundred marines to the Caribbean country to prevent Haiti from plunging into lawlessness.

But Washington requested more countries take part, and asked the UN to authorize a multinational military force. France was expected to send about 120 soldiers on Monday.

Canada has already said it's ready to send troops to Haiti as part of an international stabilization force. But Foreign Affairs Minister Bill Graham told CBC Sunday that he doesn't know when or how many soldiers will go.

• RELATED: Canada to join international force in Haiti

About 50 Canadian Forces personnel are already in Haiti, providing security to embassy staff and helping co-ordinate airlifts to safety.

Under the plan approved Sunday night, the UN-authorized troops will stay in place for three months. The soldiers will eventually be replaced by a United Nations stabilization force of police and security personnel.

Before the Security Council began its debate, Canada and other countries that make up a group called the Friends of Haiti met to discuss options and draft a resolution. The alliance includes the United States, France, Brazil, Chile and representatives of the 15-member Caribbean Community.