Media playback is unsupported on your device Media caption The BBC's Orla Guerin in Islamabad: "The target was a convoy of vehicles of the security forces"

At least 45 people have been killed and dozens have been injured by bomb attacks in the Pakistani cities of Quetta and Peshawar.

A suspected suicide bomber killed 28 people in an attack on a Shia area of Quetta, in the south-west, which has been gripped by sectarian violence.

And a bomb attack on security forces in Peshawar in the north-west left 17 people dead and more than 40 injured.

The attacks came as PM Nawaz Sharif pledged new action on terrorism.

So far it is not clear which extremist groups were behind Sunday's attacks, the BBC's Richard Galpin reports.

Over the past two weeks they have also targeted women students, foreign mountaineers and a convoy carrying a senior judge.

Mr Sharif is under mounting pressure to explain how he intends stopping the bloodshed, our correspondent says.

'Bicycle bomber'

In Quetta, members of the Shia Muslim minority have long been targeted by Sunni Muslim militants.

On Sunday evening, a suicide bomber on a bicycle tried to attack a Shia mosque but was intercepted at a checkpoint where the bomb went off, police said.

Nine women, a young girl and four boys were among those killed.

In Peshawar, hospital officials told the BBC four children were amongst those killed in an attack near the city.

A bomb was placed inside a car parked on the side of the road in a busy market area just south of the city.

The target was a convoy of troops but all those reported to have been killed were civilians.

The attack came during a visit to Pakistan by the British Prime Minister David Cameron.

Peshawar is on the edge of Pakistan's semi-autonomous tribal region - the main militant haven from which attacks are often launched.

It has been hit by dozens of bombings and killings over recent years.

Last Monday, a senior police and his driver were shot dead in the city. Three days earlier, a suicide bomb attack on a neighbourhood populated by some of the city's minority Shia Muslims killed 15.