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 THE SCENESo great were the number of casualties that there was a shortage of beds, with many people being treated on the floor.
One unattended four-year-old boy's condition appeared to be particularly distressing. His head and legs were covered with deep wounds.
Shah Faisal, the man who brought the boy to the hospital, said that when he arrived on the scene, flames were coming out of the shops in the market.
"I could see some people trapped inside... I saw this girl lying unconscious on the road outside and I brought her here.
"But no one has come to claim her so far," he said.
Eyewitness in PeshawarThe Taliban have denied being behind this bombing, but the government blames them for a wave of attacks apparently launched in response to the army operation against their strongholds on the Afghan border.
The BBC's Syed Shoaib Hasan in Islamabad says that few people will take the Taliban's denial seriously and they remain the major suspects for the bombing - if only because few other groups would have a motive for carrying out such a devastating attack.
The blast tore through buildings in Peshawar's Peepal Mandi market street, destroying several - including a mosque - and leaving others on fire.
The market mostly sells products for women, and most of the dead were women and children.
"There was a huge blast. There was smoke and dust everywhere. I saw people dying and screaming on the road," eyewitness Mohammad Siddique told AFP news agency.
Crowds dug through rubble to rescue people.
'We will not buckle'
Medical staff appealed for people in Peshawar to give blood.
Some complained that the authorities were not prepared to deal with the aftermath of such a large attack.
'An attack of sheer hellishness'
"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.
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.
"We commit to stand shoulder to shoulder with the Pakistani people in your fight for peace and security, we will give you the help that you need in order to achieve your goal."
Last week, Pakistan launched an offensive in South Waziristan, which is considered to be the main sanctuary for Islamic militants outside Afghanistan.
Correspondents say the Peshawar blasts will come as a violent reminder for the US of the difficult task it is facing in the fight against the Taliban, both in Pakistan and across the border in Afghanistan.
MILITANT ATTACKS IN OCTOBER
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