By Patricia Zengerle
WASHINGTON (Reuters) - President Barack Obama said on Thursday U.S. military aircraft will help move refugees from the Libyan border, as he called on leader Muammar Gaddafi to leave and demanded an end to violence against the Libyan people.
The United States and countries around the world are outraged by Gaddafi's crackdown in Libya, Obama said.
"We will continue to send a clear message: The violence must stop. Muammar Gaddafi has lost the legitimacy to lead and he must leave," Obama said at a news conference with Mexican President Felipe Calderon.
Obama has called on Gaddafi to leave the oil-producing North African country in written statements issued by the White House, but this was the first time he had said so in public. He also issued a warning to any of Gaddafi's officials found to have been promoting attacks on Libyan citizens.
"Those around him have to understand that violence that they perpetrate against innocent civilians will be monitored and they will be held accountable for it," Obama said.
Obama said U.S. military and civilian aircraft would help move Egyptians now stranded at the Libyan border with Tunisia.
An organized international airlift relieved the pressure of a surge of people from Libya into Tunisia on Thursday after three days of chaos. France was providing six flights per day for the next days and British charters have also begun a shuttle to Egypt.
Obama said he had told the departments of defense and state to look at the full range of options, including a possible "no-fly" zone to prevent air attacks on the Libyan opposition.
"I don't want us hamstrung. I want us to be making our decisions based on what's going to be best for the Libyan people in consultation with the international community," Obama said.
U.S. officials have stressed they would consider imposing a no-fly zone over Libya only after taking into account all ramifications of such a serious move.
Some U.S. lawmakers have urged such a zone to help rebels fighting Gaddafi's forces, but opposition is intense among Arab nations to foreign intervention in the Libyan struggle.
"It's not as simple as moving an aircraft carrier and deploying a bunch of planes. You have to take action to make sure you have air dominance to secure the skies," Pentagon spokesman Geoff Morrell said earlier on Thursday.
(Additional reporting by Caren Bohan, Steve Holland and Missy Ryan in Washington; Writing by Patricia Zengerle; Editing by John O'Callaghan and Paul Simao)