"We strongly condemn the violence," said White House spokesman Robert Gibbs.
Over 50 people were killed and more than 100 injured in the attack, which was carried out by militants armed with guns, grenades and rocket launchers.
Denouncing the 'outrageous' attack, US Secretary of State Hillary Clinton said extremists don't want democracy to flourish in Pakistan.
"I am outraged and deeply saddened by the assault on our consulate in Peshawar. The assault was part of a wave of violence perpetrated by brutal extremists who seek to undermine Pakistan's democracy and sow fear and discord," The News quoted Clinton, as saying.
Clinton said the US was taking all necessary steps to ensure the safety of both American and Pakistani staff, and, was working closely with the authorities to bring the attackers to justice.
Earlier, the Tehreek-e-Taliban Pakistan (TTP) claimed the responsibility for the violence, and said it was to avenge the military operation and the continuous US drone strikes in the tribal areas.
A self-proclaimed spokesman of the TTP, Azam Tariq, called mediapersons in Miramshah, headquarters of North Waziristan, and warned of more attacks on American establishments in the region.
"We will continue attacks on the Americans in Pakistan and Afghanistan," Tariq said. (ANI)