Militants detonated two bombs in a busy market and attacked two police checkpoints in northern Pakistan on Thursday, killing at least 14 people, wounding scores more and testing the resolve of the government as it takes on the Taliban in the Swat Valley.

The attacks in Peshawar and Dera Ismail Khan happened within two hours of each other and a day after an assault on security forces in the eastern city of Lahore killed around 30 people. That strike was claimed by the Pakistani Taliban, who warned of further attacks unless the government called off the Swat offensive.

"Our targets are security forces, who are killing innocent people in Swat and other adjoining areas," said Hakimullah Mehsud, a deputy to Pakistani Taliban chief Baitullah Mehsud. "We regret that some innocent people were also killed in the Lahore attack, we did not want that."

He said other attacks were planned for the major cities of Multan, Rawalpindi, Lahore and the capital, Islamabad, and urged civilians to flee.

Two bombs in Peshawar were mounted on motorcycles and exploded within seconds of each other, tearing off walls and shattering windows of a row of small shops at a popular market, police and witnesses said.

"It was a sudden blast and then there was fire all around, a cloud of smoke filled the sky," said Khair Uddin, a shopkeeper whose hands and chest were left bloodied by shrapnel from the blast.

Officer Zarman Shah Khan said six people were killed; a doctor at a local hospital said 80 people were wounded.

Commando units rushed to the scene and engaged in a gunfight with suspected militants who holed up in a building near the market, local police chief Malik Naveed said. Two gunmen were shot dead and at least one other was arrested.

Less than half an hour later, a suspected homicide bomber blew up a police checkpoint on the outskirts of the city, killing four police and the attacker, said police officer Yaseen Khan.

Peshawar is the main city in northwestern Pakistan.

In Dera Ismail Khan, 150 miles south of Peshawar, a homicide bomber rammed a three-wheeler taxi into a police checkpoint, killing one police officer and two civilians, said police officer Bahawal Khan.

The military launched a major offensive in the Swat region late last month after the Taliban seized control of a neighboring district in a bold bid to extend their influence. Washington and other Western allies see the campaign as a test of the Pakistani government's resolve to take on the spread of militancy.

Brig. Tahir Hamid, the commander of military operations in Mingora, the largest town in the Swat Valley, said Thursday the militants had suffered "huge casualties" in the fighting and that up to 70 percent of the town was now under government control.

The fighting has ruined villages in the region, prompted more than 2 million people to flee and thousands of others to hunker down under stiff curfew restrictions. Aid officials warn both situations could turn into humanitarian disasters.

The military claims more than 1,000 militants have died in the month-old campaign, though access to the region is restricted and the tally cannot be independently confirmed.

In the Lahore attack, gunmen fired and lobbed grenades at offices of the police and top intelligence agency, then detonated an explosive-laden van in a busy street. Lahore is Pakistan's second-largest city, a major cultural center and a hub for the armed services.

The attack was the third on the city since March, following deadly assaults on the visiting Sri Lankan cricket team and a police academy. Officials fear militants may be choosing targets there to make the point that nowhere is beyond their reach.

Police officer Chahdhry Shafiq said police had arrested one suspect, but gave no details.

The site was cordoned off Thursday while officials from electricity and public works departments surveyed the damage. Hospital officials said 314 people were taken to three medical centers after the blast. Eighty were still being treated Thursday, including 10 in critical condition.