Two United Nations helicopters have reached a remote site in a mountainous region of Haiti where a UN surveillance plane crashed on Friday, killing all 11 peacekeepers on board.

UN spokesperson Michele Montas said the Uruguayan CASA212 twin-engine plane crashed on Friday afternoon between Port-au-Prince and the border with the Dominican Republic.

"The aircraft was on a regular reconnaissance flight," Montas said in a statement from New York.

David Wimhurst, a spokesperson for the UN mission, told the Associated Press that two UN helicopters were able to land near the crash site on Saturday morning. He added that peacekeepers have started to bring the bodies back to the Haitian capital of Port-au-Prince.

All of the victims were "blue helmets" -- a colloquial term often used to describe UN soldiers -- from Jordan and Uruguay, Clarens Renois, a reporter in Port-au-Prince, told Â鶹´«Ã½ Channel on Saturday.

"The cause (of the crash) is not known" Renois said. "We are waiting to know exactly what happened."

UN officials were flying from the UN headquarters in New York to Haiti in order to help with an investigation, he said.

However, it's not clear whether results of the probe will be made public.

"The investigation will take some time," Wilmhurst said. "Any air crash requires experts to analyze it."

Uruguay's minister of defence has confirmed that six of its soldiers died in the crash.

Montas said that UN Secretary-General Ban Ki-moon extended "his heartfelt condolences to the family members, friends and colleagues of these brave peacekeepers who lost their lives in the service of peace."

Rescuers confirmed there were no survivors after an earlier trip by land to the remote crash site.

UN police guarded the site overnight, after ambulances were ordered to return to their bases late on Friday.

Since the crash area is mountainous and far from any roads, no vehicles could travel there and rescue teams had search for potential survivors by foot.

The UN said it would bring all of the bodies back to Port-au-Prince.

No officials have indicated why the plane had been conducting a reconnaissance flight near the border. However, the area where the crash occurred is often used to smuggle cocaine from South America to Europe and North America.

A 9,000-person UN peacekeeping force has been in Haiti since 2004 when the country's president at the time, Jean-Bertrand Aristide, was toppled from power by armed rebels.

With files from The Associated Press