U.S. President Barack Obama has called Moammar Gaddafi to step down as leader of Libya, citing that the regime’s brutal crackdown on protesters questions the legitimacy of his rule.

Washington had earlier imposed sanctions against the Libyan government.

In a statement released by The White House, Obama said: “The Libyan government’s continued violation of human rights, brutalization of its people, and outrageous threats have rightly drawn the strong and broad condemnation of the international community. By any measure, [Moammar Gaddafi’s] government has violated international norms and common decency and must be held accountable. These sanctions therefore target the Gaddafi government, while protecting the assets that belong to the people of Libya.”

The president’s statement added: “Going forward, the United States will continue to closely coordinate our actions with the international community, including our friends and allies, and the United Nations. We will stand steadfastly with the Libyan people in their demand for universal rights, and a government that is responsive to their aspirations. Their human dignity cannot be denied.”

Obama’s resolutions against Libya follows an unanimous decision by the UN Security Council to impose sanctions against the Libyan regime and voted unanimously to consider atrocities committed by Gaddafi's gunmen as war crimes.

Obama reportedly told Germany’s chancellor Angela Merkel “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.

Some have criticized the U.S. for waiting this long to take a definitive stand against Gaddafi.

Gaddafi has lost the confidence of his people and he should go without further bloodshed and violence, Secretary of State Hilary Clinton explained in a statement.

The US has also revoked travel visas for senior Libyan diplomats, after having frozen assets believed to be held by Gaddafi and his family.