A large explosion at a luxury hotel in Pakistan's capital of Islamabad has injured at least five people, including several foreigners and at least one U.S. diplomat. Government officials and eyewitnesses are offering different accounts.

The blast tore through the lobby of the Islamabad Marriott Hotel, destroying much of the thick safety glass at the front of the building along with much of the furniture.

Speaking at the scene of the blast, Information Minister Sheikh Rashid Ahmed attributed the explosion to an electrical problem.

"As for the experts' final decision and conclusion, this is a short circuit? electric short circuit? and these fancy (panes of) glass were broken," he said.

Some of the hotel guests who witnessed the incident, however, say the blast was large and sudden, indicating it was from a bomb.

Ruling party official Azeem Chaudhry was eating dinner in a downstairs restaurant at the hotel when the blast occurred.

He says the explosion made a loud bang and that the ground floor immediately began filling with smoke.

The debris from the explosion was scattered outward, indicating the blast came from inside the hotel.

The well-guarded capital has generally been spared much of the violent terrorist attacks, which have plagued other parts of Pakistan.

In August, Pakistani officials say they foiled a series of planned attacks on embassies and government buildings across the city.