The FBI has joined Pakistani police hunting for possible al Qaeda links to a car bomb outside the US consulate in Karachi that killed 11 people after a previously unknown group claimed responsibility for the blast.
Witnesses said FBI officials visited the site today.
"They also took photographs and made a video of surrounding areas and the spot of the bomb attack," one witness said.
A suicide bomber rammed a white Suzuki van, packed with explosives, into a concrete barrier in front of the US consulate yesterday, setting off a huge blast that also left dozens injured.
The attack, the fourth against foreigners in Pakistan since January, prompted the United States to temporarily close its missions in Pakistan. Staff at most diplomatic missions in Pakistan had already been scaled back due to military tensions with neighbouring India.
President George W. Bush said "radical killers" were behind the bombing and vowed they would not intimidate the United States.
A previously unknown group calling itself "Al-Qanoon" (The Law) said it carried out the blast in a message to media organisations in Pakistan. It said the bomb was the start of a "jihad" against America and Pakistan's rulers.