A female suicide attacker and a handcart bomb targeted Pakistani police on Thursday, killing seven people in the first deadly attacks to hit the northwest during Ramadan, officials said.

The city of Peshawar, where the bombs struck, is on the frontline of a Taliban insurgency and borders Pakistan's lawless tribal belt that Washington calls the global headquarters of Al-Qaeda.

It was only the third time police have confirmed a woman suicide attacker in the nuclear-armed country of 167 million where Taliban and Al-Qaeda-linked bombers have killed 4,500 people since 2007, destabilising the government.

Dozens were wounded in Thursday's attacks, carried out several hours apart in the Lahori Gate area of Peshawar, a teeming city of 2.5 million, targeting first a police van and secondly a police checkpost.

"This was a female suicide bomber aged around 17 or 18 who threw a hand grenade on the police checkpost, 20 metres away from the site of the first blast, and then blew herself up," police official Shafqat Malik told AFP.

"Her vest did not explode completely. She was killed and another woman was also killed and three policemen were injured," Malik said.

There was initial confusion on whether the second woman was also carrying explosives, but police and medics later said she had not.

"The other woman is more than 60 years old. Her face is completely disfigured and beyond identification. Her body has no sign of wearing a suicide vest. We feel that she was just a passer-by," Doctor Rahim Afridi told AFP.

He said 16 people were admitted with injuries after the second blast, including a 10-year-old boy.

Police official Imtiaz Shah confirmed that the other woman was a passer by and had no connection to the woman, believed to have been around 17 years old.

In late June, the Pakistani Taliban claimed for the first time that a married Uzbek couple carried out a suicide attack on a police station that killed 10 officers and threatened further husband-and-wife bombings.

Police said five officers and a child were killed earlier when a bomb hidden in a handcart on the roadside tore through a passing police van carrying 20 personnel at 7:10 am (0210 GMT), updating an initial death toll of five.

Eighteen other people were wounded, said police official Muhammad Faisal.

Shattered glass, human flesh, blood and police uniforms littered the area after the bomb, an AFP reporter said.

"The police van was carrying 20 policemen," said Imtiaz Shah, another police official, adding the vehicle was wrecked and that a group of schoolboys had been in the area when the bomb exploded.

"A 12-year-old boy has also been killed," he said.

Witness Mohabbat Khan, 45, told AFP that volunteers helped police evacuate the casualties after the attack, after he saw clouds of smoke and dead bodies littered on the ground.

Government security forces have been humiliated by some of the most daring attacks in a four-year bombing campaign that erupted after troops targeted extremists holed up in an Islamabad mosque in July 2007.

Peshawar police chief Imtiaz Altaf told AFP that officers had killed a suspected Taliban suicide bomber and his handler in an overnight gunbattle at Matani, on the outskirts of the city.

Militants bitterly oppose Islamabad's US alliance in the war against the Taliban in neighbouring Afghanistan and US drone strikes on Pakistani soil, which leaked American diplomatic cables showed the government quietly approved.

On Wednesday, a US drone strike in the North Waziristan tribal district killed up to 21 Afghan fighters from the Al-Qaeda-linked Haqqani network, considered the top US foe across the border in eastern Afghanistan.

US officials have accused Pakistani intelligence of playing a double game with extremists, including the Afghan Taliban and the Haqqani network, in order to exert influence in Afghanistan and offset the might of arch-rival India.

Washington's pressure on Islamabad to launch a decisive military campaign in North Waziristan, as Pakistan has conducted elsewhere in the tribal belt, has so far been ignored.