Port-au-Prince, Haiti ? U.N. troops are coming back to Haiti, but after a decade of failed missions many in the traumatized nation wonder whether the peacekeepers — cobbled together from countries ranging from Argentina to Zimbabwe — are up to the daunting task.

Although the official handover is today, only 42 of some 8,000 promised troops and police have arrived.

Brightly colored flags of 30 participating nations dot empty barracks at the airport. And only samples of the blue U.N. headgear have arrived.

Floods that killed nearly 1,700 people last week and stranded thousands in remote villages have forced U.S. troops to stay past their June 1 departure date. American and French forces in the four-nation group handing the baton to the United Nations are the only ones with helicopters to bring aid to otherwise unreachable villages.

Unless they get new marching orders, the 1,900 U.S. troops will leave at the end of June, many to return to combat in Iraq.

Some Canadian, Chilean and French troops — from the 3,600-soldier force that arrived in February when a rebellion ousted President Jean-Bertrand Aristide — will join the U.N. force for up to six months.

“We’ve done an excellent job in working with the multinational task force and we look forward to working with the other nations,” said Canadian Capt. David Devenney.

The U.N. force, to include 6,700 troops and 1,622 civilian police, will be led by 1,200 Brazilian troops, the largest contingent the South American country has sent on a U.N. mission.

Cpl. Patricio Tapia of the Chilean Navy walks between U.N. cars upon their arrival in Port-au-Prince, Haiti. Chile is participating as part of the U.N. force, which is planned to include about 6,700 troops and 1,622 international police in Haiti. Whether the force will reach full strength is unclear.

But Brazilian Army Gen. Augusto Heleno Ribeiro Pereira recently warned Haitians not to expect miracles. Heleno, commander of the U.N. force, is to arrive today with another 150 troops.

The U.N. mission will again try to keep a tentative peace in the divided country and train an ill-equipped and understaffed police force.

U.N. Secretary-General Kofi Annan has asked for a long-term U.N. commitment to transform Haiti — which has suffered more than 30 coups in 200 years — into “a functioning democracy.” But only a fraction of the $35 million in requested aid has arrived.