At least 91 people have been killed after a huge car bomb ripped through a busy market in Peshawar, Pakistan.
The attack, which injured at least 200 others, was the deadliest to hit Pakistan this year.
Similar attacks have killed hundreds of people in recent weeks, as the army carries out an operation against Taliban militants in South Waziristan.
The blast came as US Secretary of State Hillary Clinton began a visit to the Pakistani capital, Islamabad.
Mrs Clinton told a news conference the US was "standing shoulder to shoulder" with Pakistan in its fight against "brutal extremist groups".
At least 91 people have been killed after a huge car bomb ripped through a busy market in Peshawar, Pakistan.
The attack, which injured at least 200 others, was the deadliest to hit Pakistan this year.
Similar attacks have killed hundreds of people in recent weeks, as the army carries out an operation against Taliban militants in South Waziristan.
The blast came as US Secretary of State Hillary Clinton began a visit to the Pakistani capital, Islamabad.
Mrs Clinton told a news conference the US was "standing shoulder to shoulder" with Pakistan in its fight against "brutal extremist groups".
There were a lot of wounded people. We tried to help them but there were no ambulances so we took the victims on rickshaws and other vehicles," Muzamil Hussain told the Associated Press.
"There were no police. The police and government didn't help us, the police even opened fire on us."
Security has been stepped up across Pakistan, but the government still appears to be unable to stop the attacks, the BBC's Mark Dummett in Islamabad says.
Foreign Minister Shah Mahmoud Qureshi promised that the country's resolve would not be shaken by "such heinous crimes".
At a news conference in Islamabad with Mrs Clinton, he told potential militants: "We will not buckle, we will fight you. We will fight you because we want stability and peace in Pakistan."
'Brutal extremists'
Mrs Clinton is in Pakistan to discuss US concerns about the increasing numbers of militant attacks and the security of the country's nuclear weapons.
Hillary Clinton: "In recent weeks Pakistan has endured a barrage of attacks"
She condemned the "vicious and brutal" attack in Peshawar and said the fight against the Taliban was "not Pakistan's alone".
"Pakistan is in the midst of an ongoing struggle against tenacious and brutal extremist groups who kill innocent people and terrorise communities," she said.
There were a lot of wounded people. We tried to help them but there were no ambulances so we took the victims on rickshaws and other vehicles," Muzamil Hussain told the Associated Press.
"There were no police. The police and government didn't help us, the police even opened fire on us."
Security has been stepped up across Pakistan, but the government still appears to be unable to stop the attacks, the BBC's Mark Dummett in Islamabad says.
Foreign Minister Shah Mahmoud Qureshi promised that the country's resolve would not be shaken by "such heinous crimes".
At a news conference in Islamabad with Mrs Clinton, he told potential militants: "We will not buckle, we will fight you. We will fight you because we want stability and peace in Pakistan."
'Brutal extremists'
Mrs Clinton is in Pakistan to discuss US concerns about the increasing numbers of militant attacks and the security of the country's nuclear weapons.
Hillary Clinton: "In recent weeks Pakistan has endured a barrage of attacks"
She condemned the "vicious and brutal" attack in Peshawar and said the fight against the Taliban was "not Pakistan's alone".
"Pakistan is in the midst of an ongoing struggle against tenacious and brutal extremist groups who kill innocent people and terrorise communities," she said.
