A suicide bomber has killed himself and one other at a top hotel in Pakistan's capital, Islamabad, officials say.
Hotel staff cover one of the bodies
Police have sealed off the blast area in the car park of the Marriott hotel.
"It was a suicide attack. The bomber and one security official of the hotel were killed," Interior Minister Aftab Sherpao told Reuters news agency.
The Marriott is located near government buildings and diplomatic missions. Police say at least five people hurt in the explosion were taken to hospital.
Witnesses say the bomber tried to enter the hotel through a back door that is used by staff.
He was stopped by the security guard and detonated his explosives after a scuffle.
The BBC's Barbara Plett at the scene says part of the hotel and a number of cars were also damaged.
Frightened hotel guests spoke of chaos after the explosion, which could be heard in other parts of the city.
"I was taking lunch at the Royal Elephant Thai restaurant inside the Marriott when the entire restaurant was shaken by a bang," one guest, Mohammed Aamir, told the AFP news agency.
"It literally shook us out of our seats. It was a huge bang. We rushed outside and there was chaos."
The city's Poly Clinic hospital said it was treating four of those injured in the explosion.
"One is serious and three others have minor injuries," doctor Murtaza Nadeem told AFP.
The Marriott was due to host a reception later on Friday marking the 58th Republic Day of Pakistan's neighbour and rival, India. It is not clear if there is any link with the bombing.
Some observers say the bomber may have been trying to target a bar in the hotel's basement where Westerners and other foreigners gather.
But they point out that if he had wanted to inflict maximum damage he would have entered by the front door, although it is much more heavily guarded.
Security at the Marriott is tight, with guests and vehicles subjected to checks. An explosion at the hotel in October 2004 injured five people.
The US embassy warned its staff to stay away from the Marriott after the blast, even though it was blamed by Pakistan's authorities on an electrical short circuit.
Bombings are fairly frequent in Pakistan, and are often blamed on Islamic militants angered by President Musharraf's support for the US-led "war on terror" and by his efforts to make peace with India.
But there have been few attacks in the purpose-built capital itself, where security is easier to maintain.
High security alerts were called in the cities of Karachi and Peshawar following Friday's blast.
There has also been a security alert in Islamabad, related to army operations in the tribal areas near the Afghan border and threats by the militants there to avenge them.