Several thousand people have protested in the Pakistani city of Peshawar against a US missile strike which killed 18 people last week.
Hardline Islamic groups have led the protests
The attack apparently targeted al-Qaeda's deputy Ayman al-Zawahiri.
He is not thought to have been present, but Pakistan says a number of foreign militants died. Unconfirmed reports say three top al-Qaeda figures were killed.
The attack was condemned by Pakistan's government which said it could not accept such actions.
Friday's protest was organised by two hardline Islamic parties, which oppose the US-led "war against terrorism".
A number of villagers lost their homes in the strike
Up to 3,000 protesters set off from two different mosques chanting "Death to America" and "Jihad [holy war] is our way".
Heavy security was in place, with police deployed on roofs and armed with tear gas launchers and assault rifles.
The BBC's Barbara Plett, who is in Peshawar, says the anti-American anger has not led to sustained mass protests.
The attack took place in the tribal area bordering Afghanistan.
The US has about 20,000 troops in Afghanistan, but Pakistan does not allow them to operate across the border.
Pakistan has about 70,000 troops in the border region hunting al-Qaeda and Taleban remnants.