President Barack Obama called on Saturday for Libyan leader Muammar Gaddafi to step down from power, sharpening U.S. rhetoric after days of deadly violence and criticism that Washington was slow to respond.
Obama, in a call to German Chancellor Angela Merkel, said Gaddafi had lost his legitimacy and needed to go.
"The president stated that when a leader's only means of staying in power is to use mass violence against his own people, he has lost the legitimacy to rule and needs to do what is right for his country by leaving now," the White House said in a statement describing the call.
"The president and the chancellor shared deep concerns about the Libyan government's continued violation of human rights and brutalization of its people."
Previously the White House has stopped short of calling for Gaddafi to leave, saying -- just as in other countries affected by a wave of regional unrest -- that only Libya's citizens had a say in choosing their rulers.
Secretary of State Hillary Clinton, echoing Obama's tougher stance, said Libyans had made their preferences on that issue clear.
"We have always said that the (Gaddafi) government's future is a matter for the Libyan people to decide, and they have made themselves clear," Clinton said in a statement.
"(Muammar Gaddafi) has lost the confidence of his people and he should go without further bloodshed and violence."
The Obama administration had been criticized for its relatively restrained response so far to Gaddafi's bloody crackdown on an uprising against his four-decade rule.
But White House officials said fears for the safety of Americans in the country had tempered its response to the turmoil. Washington announced a series of sanctions against Libya on Friday after a chartered ferry and a plane carrying Americans and other evacuees left Libya.
Gaddafi's grip on power appeared more tenuous on Saturday. One of his former ministers announced the formation of an interim government to reunite the country.
Libya's ambassador to the United States, Ali Aujali, told Reuters he supported that caretaker government being formed by former Libyan Justice Minister Mustafa Mohamed Abud Ajleil.
Clinton said she signed an order directing the State Department to revoke U.S. visas held by senior Gaddafi government officials, their family members and others responsible for human rights violations in Libya.
"As a matter of policy, new visa applications will be denied," she said.