US President Barack Obama speaks about Libya while U.S. Secretary of State Hillary Clinton listens in the White House in Washington February 23, 2011.[Photo/Agencies]

WASHINGTON - US President Barack Obama on Wednesday said the violent crackdown in Libya violated international norms and that he had ordered his national security team to prepare the full range of options for dealing with the crisis.

"It is imperative that the nations and peoples of the world speak with one voice," Obama told reporters in his first public comments on the turmoil in Libya, where leader Muammar Gaddafi is facing a revolt against his 41-year rule.

Obama urged an end to attacks on peaceful protesters but stopped short of calling for Gaddafi to step down as ruler of the oil-producing North African nation and did not lay out ay specific measures under consideration against the Libyan government.

"The suffering and bloodshed is outrageous and it is unacceptable," Obama said at the White House with Secretary of State Hillary Clinton at his side. "These actions violate international norms and every standard of common decency. This violence must stop."

Obama said Washington was coordinating further steps with allies and the international community. "I have also asked my administration to prepare the full range of options that we may have to respond to this crisis," he said.

Obama has faced criticism in some quarters for not speaking out sooner, but U.S. officials say they have tempered their response to ensure Americans in Libya were safely evacuated and out of harm's way.

The Obama administration said earlier that it was looking at imposing sanctions on Libya to punish it for a violent crackdown on protesters seeking Gaddafi's ouster.

The State Department said freezing Libyan assets, including those belonging to Gaddafi, were among the options being considered, and some U.S. lawmakers have urge direct action such as imposing no-fly zones.

But U.S. options to influence events in Libya are limited, unlike in Egypt and Bahrain where Washington was able to bring pressure to bear as a long-time ally and benefactor.