A suicide car bomb attack killed at least 20 people in a crowded market place in a northwestern Pakistani city on Tuesday, a senior police officer said.

District Police Office Riaz Khan said that over 40 other people were also injured in the attack in Charsadda, a city some 30 kilometers north of Peshawar, the capital of North West Frontier Province.

Khan said he and a group of police men escaped the attack as it occurred hardly a few minute after they passed by at 4:30 p.m. local time (1130 GMT).

The police chief said that he and the local police recently received threats. He said that no police man died or was injured in the attack and all casualties are civilians.

People shifted the injured to the nearby District Headquarters Hospital in private cars. Several injured were shifted to Peshawar, doctors said. Two injured are in critical condition, they said.

Over 50 shops and many vehicles in the market were also destroyed in the blast at Farooq Azam Chowk in the city's center at 4:40 p.m., local TV reports said.

Witnesses said that the blast ripped through a crowded square at a time when a large number of people were busy with shopping. The square also crowded as people belong to other areas board passenger vans from the same place.

No group claimed responsibility for the blast. But the Pakistani government blames Taliban militants for such attacks.

Pakistani President Asif Ali Zardari and Prime Minister Syed Yousuf Raza Gilani have strongly condemned the car bomb blast in Charsadda on Tuesday evening. The two leaders, in separate messages, reiterated their resolve to fight terrorism and militancy and not to allow anyone to disrupt peace in the country. The prime minister also directed the concerned authorities to offer every possible medical treatment to the injured in the blast.

A strong wave of attacks in the recent month have killed more than 200 civilians in Pakistan's northwest and it was the third back-to-back suicide blast in and around Peshawar in three days. On Monday a suicide attack killed at least three people including a police man in the city. Another suicide bomber killed 13 people including a local mayor in Peshawar on Sunday.

Meanwhile in a daily press release, the Pakistani army said Tuesday that the security forces have taken full control of the town of Makeen, which is considered as the base headquarters of Taliban militants in the South Waziristan tribal agency, and killed another nine militants during the last 24 hours, bringing the total fatality to over 500, as the operation in the northwest tribal area progressed towards the Taliban strongholds.