PORT-AU-PRINCE (AFP) - US Secretary of State Hillary Clinton arrived in Haiti Saturday to meet President Rene Preval and help speed up an urgent bid to clear logistical hurdles to deliver aid to quake-hit Haitians.

Clinton, who arrived in the devastated capital Port-au-Prince aboard a US Coast Guard plane shortly before 2000 GMT, is the highest-ranking US official to visit Haiti since Tuesday's deadly quake.

On landing she headed into a tent set up at the Port-au-Prince -- the hub of the massive international relief operation -- for talks with the head of the US military relief operations in Haiti, Lieutenant General Ken Keen, US Ambassador Kenneth Merten, and US Agency for International Development (USAID) Administrator Rajiv Shah.

She then met for about an hour with President Rene Preval. Clinton said before arriving she would ask how the United States could help tackle fuel shortages and other logistical problems that were dogging the relief effort.

She wanted to "listen to him, to be sure we are as responsive as we need to be."

Clinton and USAID director Shah said the UN World Food Program had begun setting up food and water distribution centers at 14 points across the capital. "We're looking to expand that," Shah said.

Clinton said criticism that aid was piling up at the airport was unfair, saying US forces, in charge of the airport, were getting it out as quickly as possible.

Shah said he understood some distribution points were already working, roads had been cleared, and the US military is prepared to provide security at these sites as well as transport supplies to them.

Clinton made clear that the 7,000 Brazil-led UN force, deployed for years in the country with wide knowledge and local informants, was responsible for security.

"We are working to back them up, but not to supplant them," she said.

The US military was also trying to establish helicopter landing zones for some aid deliveries but had to drop the plan when it realized Haitians would mob the site each time and make it dangerous to land, she said.

Aid would also be shipped aid outside the capital, as Haitians were beginning to trickle out to the less damaged areas of the country, she said.

"The other thing we're trying to do is get our helicopters outside the immediately affected area, outside of Port-au-Prince, because people are leaving the city," Clinton said.

"They are seeking medical help. They are trying to get to relatives," she added. "The countryside is relatively unaffected... We're trying to get ahead of the curve here."

She noted that a number of injured Haitians managed to reach a hospital about 50 miles (80 kilometers) outside the capital, but it was now full of patients.

Clinton said State Department officials had asked the US military whether supplies could be parachuted to Haitians, but heard: "They won't do that. They don't think that's a good idea. It's too dangerous."

"You can do that in rural areas. In urban areas, it causes riots... and causes injuries to people," she said, noting that packages could fall on crowds.

Philip Crowley, Clinton's spokesman, said there were hopes to make the northern city of Cap Haitien operational as a container port, which would give the country a second port, but he gave no details.

When Clinton departs Haiti she will take with her 50 US citizens who had been living in Haiti, some of them to Jamaica and others to the United States, officials said.

Ann Young Lee, a relief worker with the humanitarian aid group CHF International and one of six relief workers on Clinton's plane, said she is based in Haiti but was on leave when the quake struck.

"It's been tough" hearing what happened, Lee said. "The Haiti I knew and love is not going to be there. I'm just trying to brace myself for it."

By Lachlan Carmichael, AFP, January 16, 2010