At least 57 people have been killed and more than 100 wounded in an explosion at a market in the northwest Pakistan city of Peshawar, according to medical officials.
The blast rocked a women's market in Peshawar, the latest attack to shake the country as the army battles Islamist militants along the Afghan border.
The death toll in Wednesday's attack is expected to rise, according to medical officials.
An AP Television cameraman at the scene of the blast said many stores in the area had been destroyed.
He described seeing firefighters tackling blazes caused by the explosion, and both civilians and rescue workers trying to pull wounded people from the rubble of collapsed buildings.
Video from Lady Reading Hospital (LRH) one of the largest medical facilities in the area, showed seriously injured people being taken from ambulances and civilian vehicles into the building for treatment.
The explosion hit Peepl Mandi, a neighbourhood in the city where many Shiite Muslims live.
Police officials said it struck the Mina Bazaar, which caters to female shoppers.
The area was full of smoke and very congested, and ambulances were stuck in traffic, according to officials.
No group immediately claimed responsibility, but Peshawar has been the site of many of the attacks staged by Islamist militants this month, a wave of bloodshed that has killed more than 200 people.
The Taliban have warned Pakistan that they would stage more attacks if the army does not end its offensive in South Waziristan tribal region, where the military has dispatched some 30-thousand troops to flush out insurgents.
The blast coincided with a trip to Pakistan by US Secretary of State Hillary Rodham Clinton.
She was three hours drive away in the capital of Islamabad when the blast took place.