Updated

Sixteen countries have offered to provide the 3,500 extra troops and police officers that the United Nations requested to beef up security in Haiti and ensure aid is delivered to earthquake victims, the U.N. peacekeeping chief said Thursday.

A week after the Jan. 12 quake devastated the Haitian capital and surrounding area, the U.N. Security Council authorized 2,000 additional troops to help the 7,000 military peacekeepers already in the country and 1,500 extra police for the 2,100-strong international police force.

"The international answer to our request has been tremendous," Undersecretary-General for Peacekeeping Alain Le Roy told reporters Thursday. "The answer has been remarkably rapid. ... We have now all the pledges we needed for both the 2,000 military and for the 1,500 policemen."

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Le Roy said he expects the 2,000 extra troops to be on the ground in Haiti within three weeks to help escort humanitarian convoys and ensure security while aid is being distributed.

He said 900 Brazilian soldiers would be arriving on Thursday and Friday.

The advance party of a 190-member Japanese military engineering company has already arrived, and the advance party of a 240-member South Korean engineering company will be in Haiti by Saturday, he said. Some 150 troops from the neighboring Dominican Republic are in the process of deploying along the border, and troops from Argentina, Peru and Uruguay will be arriving soon, he said.

Le Roy said about 500 police from Spain, the Netherlands, France, Bangladesh and Italy will be there in within two weeks. U.N. officials said a 100-strong French police unit that came in after the quake will become part of the U.N. contingent.

The remaining 1,000 police — from Bangladesh, India, Turkey, Pakistan and Rwanda — will arrive in April or May, Le Roy said.