US Marines staying at the Marriott Hotel in Islamabad may have been the target of Saturday's suicide attack.

Police have reported about 30 Marines were staying at the hotel and were scheduled to leave for Afghanistan early Sunday morning.

One official said that the American security personnel were in Pakistan for the just-concluded visit by the Chairman of the US Joint Chiefs of Staff, Admiral Michael Mullen.

But another source said that they were in Islamabad only for two days and were scheduled to leave for Afghanistan on Sunday morning.

A senior security official has said: “We believe that they were the target of the suicide attack, otherwise, we can't find any other reason for such an attack.”

The official said that soon after the blast, US embassy officials reached the spot and were seen looking for the Marines who, according to the sources, were staying on the fourth floor of the hotel.

The fourth floor was among the worst affected as the entire hotel turned into a blazing inferno.

Besides the Marines, the staff of Saudi Airlines and a number of foreigners were staying at the Marriot.

Police sources said that the dead include three Koreans, two Saudis and one American.

Among the injured are some foreigners, including some Americans who were shifted to the hospital inside the US Embassy.

Unconfirmed reports also said that a senior US security official was among the injured.