Dozens of others were injured by the powerful bomb, which was planted beneath a gypsy vendor's cart near a public park in the city, North West Frontier Province police chief Riffat Pasha told AFP.

Six dead bodies and dozens of injured people had been brought to the Lady Reading hospital in Peshawar, a doctor at the hospital said, while police said the number of injured was at least 21.

"I heard a big explosion and as I looked back there was human flesh all around," an eyewitness who gave his name as Shahid told AFP at the scene of the explosion.

The carts which were parked on the footpath outside the frontier city's Jinnah Park were selling toys, garments and jewellery ahead of next week's holiday of Eid-ul-Fitr, police officer Abdul Rehman said.

The holiday marks the end of the Muslim fasting month of Ramadan.

The explosion sent limbs flying metres (yards) away from the site of the blast and the road was littered with blood and pieces of flesh, an AFP photographer at the scene said.

Many people were crying at the site which was in a state of chaos, the photographer added.

Pakistan has suffered a number of bomb blasts in recent years blamed mainly on Islamic extremists opposed to the pro-US policies of President Pervez Musharraf or militants from the rival Sunni and Shia Muslim sects.

There was no immediate claim of responsibility for the latest attack.

Earlier two Pakistani soldiers were killed and three others injured when rockets fired by Islamic militants hit a checkpost in a restive tribal area bordering Afghanistan, officials said Friday.

Militants fired some 40 rockets and mortar shells late Thursday at the Ganji Tekri checkpost in the Shakai valley area of South Waziristan, a security official told AFP on condition of anonymity.

The soldiers returned fire and the clash continued until dawn on Friday but there were no reports of any militant casualties, the official said.

South Waziristan has been relatively quiet since the military launched major offensives in 2004 against al-Qaeda and Taliban militants who fled the US-led invasion of Afghanistan.

The scenic Shakai Valley lies some 25km north of Wana, the tribal district's main town.

The government last month signed a peace deal with militants and tribal elders in neighbouring North Waziristan, under which insurgents are supposed to stop cross-border attacks on Nato and coalition forces in Afghanistan.