An explosion in the Marriott hotel in Islamabad, Pakistan has injured at least five people -- although it is unclear what caused the blast.
The US State Department says a US embassy staffer was among the injured. Foreigners were also injured in the blast.
The blast tore through the lobby of the hotel.
Pakistani Information Minister Sheikh Rashid Ahmed attributed it to an electrical problem, while Interior Minister Aftab Ahmed Khan Sherpao says there was no evidence of terrorist activity or a bomb blast.
But some hotel guests who witnessed the incident say the blast was large and sudden, indicating it was from a bomb.
Pakistani Television quoted police as saying it was an explosion, not a short circuit.