ISLAMABAD: A suicide attacker struck a security checkpoint in northwest Pakistan on Saturday, killing at least seven people and injuring 26.

The attacker — who was in a three-wheeled auto-rickshaw — detonated explosives in the Saidu Sharif town of Swat district, police official Qazi Farooq said.

Army spokesman Maj. Mushtaq Khan said a soldier, a policeman and five civilians died in the attack. Soldiers and policemen were among the 26 injured, he said.

Khan said the checkpoint was being jointly manned by troops and police. The blast also damaged several vehicles, and the victims were transported to a nearby hospital, he said.

The Pakistani military launched a major offensive in Swat early last year after peace deals with local Taliban collapsed.

The military took back the Swat Valley by mid-2009, but sporadic violence has continued.

No one claimed responsibility for Saturday's attack, but the suspicion fell on militants who have stepped up attacks against police and security forces in recent months.

The attack came a day after two suicide bombers killed 43 people in near-simultaneous blasts in the eastern city of Lahore.

Friday's bombings also wounded about 100 people, raising fears of a new wave of attacks by Islamic militants.

Underscoring the widespread fear, a series of small explosions injured at least three people and sparked panic in another Lahore neighborhood late Friday night. Police officials said the five low-intensity blasts apparently resulted from loose explosives scattered through the residential area of Iqbal Town. While the explosions terrified residents and sent police and rescue workers racing through town, there were no reports of deaths or major damage.

The second major attack in Lahore this week saw two suicide bombers, who were on foot, set off their explosives within seconds of each other near two trucks carrying soldiers on patrol in RA Bazaar, a residential and commercial neighborhood with numerous military buildings. About 10 of those killed were soldiers, said Police Chief Parvaiz Rathore.

Security forces swarmed the area as thick black smoke rose and bystanders rushed the wounded into ambulances. Video shot by a cell phone just after the first explosion showed a large burst of orange flame erupting in the street, according to GEO TV, which broadcast a short clip of the footage shot by Tabraiz Bukhari.

"Oh my God! Oh my God! Who are these beasts? Oh my God!" Bukhari shouted after the blast in a mixture of English and Urdu.

No group immediately claimed responsibility, but suspicion quickly fell on the Pakistani Taliban and al-Qaida, which have been fighting to destabilize the U.S.-allied Islamabad government.

They launched a bloody wave of bombings last fall across Pakistan, leaving 600 people dead in near-daily attacks done in apparent retaliation for an army offensive against the insurgents' main stronghold, in the tribal region of South Waziristan along the Afghan border.

The government offensive was seen as fairly effective, forcing many Taliban leaders to flee and reducing the area where the insurgents could operate openly.

The insurgent attacks slowed early this year. In recent months, they have been smaller, farther apart and largely confined to remote regions near Afghanistan.

But on Monday, a suicide car bomber struck a building in Lahore where police interrogated suspects — including militants — killing 13 people and wounding dozens. The Pakistani Taliban claimed responsibility.

Also this week, suspected militants attacked the offices of a U.S.-based Christian aid group in northwestern Pakistan, killing six Pakistani employees, while a bombing at a small, makeshift movie theater in the city of Peshawar killed four people.