The Pentagon has sent about 1,600 US troops, mostly Marines, to Haiti and could send more if theUS commander there requested, a senior Pentagon official said Tuesday.

Marine General Peter Pace, vice chairman of the Joint Chiefs ofStaff, told a Pentagon briefing that the 1,600-odd troops were within the 1,500 to 2,000 range previously provided by the Pentagon.

"And the commanders on the ground will make sure the secretary understands what they need, and I'm sure he'll provide," he said.

Pace said France, Chile and Canada have sent a total of about 700 troops to Haiti and there are other countries that are lookingto increase their contributions.

Defense Secretary Donald Rumsfeld said the Pentagon is already working on the follow-on force, a UN authorized multinational force led by the US troops. He said the Pentagon hopes the UN force "will come in within 90 days."

At the briefing, Pace defended the killings of two Haitians by the US Marines in separate incidents, saying the Marines were acting within their orders to fire when they felt threatened.

"What I was told this morning when I came in was that there wasa vehicle that was traveling at a high rate of speed and aimed itself at the Marines; had they not fired, they would have been hit by the vehicle," Pace said.

He was referring to the killing of a driver by Marines late Monday. On Sunday, US Marines shot and killed a gunman who they said fired at them during a demonstration, which left seven peopledead and more than 30 wounded.