President Clinton is acknowledging the failure of his policy toward Haiti and will seek United Nations support for a broad trade embargo against the Caribbean nation, an official says.

In a separate development, State Department spokesman Mike McCurry said that a boatload of 411 Haitians off Florida will not be turned back as is customary with the U.S. repatriation policy. The migrants were to be brought ashore by the Coast Guard and processed by the Immigration and Naturalization Service because of "extraordinary circumstances" including the fact that their 65-foot freighter was severely overcrowded, many passengers were in poor physical condition and the boat "was without adequate safety equipment," he said.After six members of Congress were arrested Thursday for illegally protesting Clinton's policy on the White House sidewalk, a White House official disclosed the president will ask the United Nations to back an embargo on all but food and humanitarian aid going Haiti. The move, which caps several weeks of policy review by the administration, could come as early as next week, said the official, who spoke on condition of anonymity.

"The president has understood that the policy has not been successful and it was time to change the strategy," the White House official said. U.S. policy is aimed at returning exiled President Jean-Bertrand Aristide to power and restoring the democratic system that elected him.

Clinton has come under increasing pressure from Congress to take tougher steps against Haiti's military regime, with legislation introduced in both the House and Senate calling for a full embargo and other steps.

Press Secretary Dee Dee Myers said the president decided that tightening sanctions is the best next step "because there has been an increase in violence and the political process has stalemated."

On Thursday, Aristide lashed out at Clinton, claiming the president did not care about Haiti and lacked the "political will" to deal with its problems. He also had called Clinton's Haitian policy "a cynical joke. It's a racist policy. It's really a way to say we don't care."

Myers rejected Aristide's characterizations. "Of course it's not a race-based policy," she said. "The policy of direct return (of Haitian refugees) is in our view the most humanitarian approach. To create a situation where literally tens of thousands of Haitians could be fleeing in boats that aren't seaworthy and to risk their lives at sea, is a situation that we don't want to encourage."

A source close to Aristide said his full reaction to the new administration plan was not known but that it "sounds largely consistent with what he's been advocating."