A car bomb tore through a Pakistani refugee camp Thursday, killing 15 people including women and children and heightening security fears before a May general election.
More than 40 other people were wounded when the bomb exploded at Jalozai, the country's largest refugee camp, as scores of people queued for rations.
Jalozai is home to tens of thousands of people displaced from the tribal belt, a stronghold of Taliban and Al-Qaeda-linked militants, on the Afghan border and is close to the main northwestern city of Peshawar.
There was no immediate claim of responsibility.
But officials linked the attack to fighting in Khyber district, where the military has stepped up an offensive against Taliban and local militia, and from where most camp residents have fled.
"The bomb exploded in a car parked near the administration office where refugees had lined up to get rations and new arrivals were being registered," said camp police official Fuad Khan.
District police chief Mohammad Hussain said the bomb was detonated by a timer and carried up to 35 kilograms (77 pounds) of explosives and mortar bombs.
An AFP reporter saw scenes of devastation, with pieces of flesh and blood splattering the area.
Spilt grain and children's food supplements littered the ground next to discarded toys, sandals and twisted metal. The engine of the car which exploded lay around 50 feet (15 metres) from a two-foot crater left by the blast.
Tariq Khan, a 40-year-old displaced driver from Khyber, said he was in his tent when he heard a "very loud" blast and saw thick black smoke.
"I rushed to the spot and saw bodies lying in a pool of blood and wounded people crying in pain. I saw small pieces of human flesh everywhere and found my uncle, both of whose legs had gone, and he was crying with pain," Khan told AFP.
"I lifted him and looked for a car and luckily found one nearby and took him to hospital," he said.
Jehanzeb Khan, 27, another refugee from Khyber, also helped to rescue the wounded.
"I saw bodies, blood and wounded everywhere. I started lifting the wounded and put them in the cars and ambulances and the white clothes I put on this morning turned all red with blood," Khan said.
Local administration official Ayaz Khan Mandokhel said 15 people were killed, including two children aged around eight and 10 and three women.
Hussain, the police official, confirmed the death toll. "There are 41 injured, four of them are in a critical condition," he added.
Rations were being handed out by a local charity BEST in partnership with the United Nations and the US Agency for International Development.
Mohammad Ashraf, project director at BEST, a UN partner, said a 30-year-old female member of staff who worked on hygiene was killed. Nine other members of staff who were distributing food were wounded, he said.
Aside from the election, the bombing will raise concerns about the safety of aid workers in the northwest, where seven charity staff were shot dead on January 1 and where those working on polio eradication have also been targeted.
Most of those now in Jalozai, built originally to host Afghan refugees, come from Khyber, where the army is battling the Taliban in the Tirah valley to try to safeguard the election and crack down on militants behind attacks.
"People of different areas are living here in this camp and the bombing appears to be the result of rivalry between the groups in Khyber and the ongoing fighting between them," a senior police official told AFP on condition of anonymity.
The May 11 vote will mark the first time that an elected civilian government hands over to another in a country that has seen three military coups and four military rulers since independence in 1947.
Security has worsened markedly since the last election in 2008. During that campaign, former prime minister Benazir Bhutto was assassinated at a rally in Rawalpindi, an attack blamed on the Pakistani Taliban.
A parliamentary committee has until Friday to select a candidate to head an interim administration, which will guide the country through the campaign period.