The United States has threatened to reduce a 1.5 billion US dollar program of foreign aid to Egypt based on President Hosni Mubarak's response to swelling protests in his country.

White House spokesman Robert Gibbs said violence is not the response to the demands for greater freedom. He called it an important opportunity to introduce concrete and legitimate political reforms to address the deep concerns of the Egyptian people and make some substantive progress.

Gibbs also asked Egypt's security forces and demonstrators to refrain from violence. He noted that the White House is monitoring the situation in Egypt very closely. But he said US President Barack Obama has not tried to speak with Mubarak by phone.