Pakistan's army said Sunday it reclaimed several areas including the central square in Mingora, the largest city in the contested Swat Valley where it has been trying to root out al-Qaeda and Taliban insurgents.

Troops engaged in street fights and encountered at least 12 roadside bombs while securing eight intersections in Mingora, Pakistan's army said Sunday in a release.

Five suspected militants were killed in various parts of Mingora while 14 others were arrested, the army said.

Fighting intensified last month after a peace deal between the regional government and hardline cleric Sufi Muhammad failed to take hold, and a military operation was launched to expel the Taliban from their stronghold in the Swat.

Hundreds have died and nearly 1.9 million people have fled the region since the fighting began a month ago.

Washington has pressed Islamabad to crack down on al-Qaeda and Taliban strongholds along the Afghan frontier, saying the militants threaten not only U.S. and NATO troops in Afghanistan, but also Pakistan's existence.

Capturing Mingora is critical to government efforts to regain the valley in the north of Pakistan and prevent it from being a safe haven for insurgents.

Thousands of civilians began fleeing Mingora last week ahead of the troop advance, but between 10,000 and 20,000 are still stranded in the city, which normally has a population of about 375,000.

In their retreat from Mingora, the Taliban left many mutilated bodies in the town square that Pakistanis in the Swat Valley's main town took to calling "bloody intersection."

The militants would leave their victims' bodies there — some decapitated and some killed in other brutal fashions.

The advances in Swat came Sunday as helicopter gunships pounded alleged militant hideouts in a nearby tribal region, killing at least 18 people, while police announced the arrest of a militant commander and six other Taliban fighters elsewhere in the northwest.

The military said about 1,100 suspected insurgents have died so far in the month-long offensive in Swat and neighbouring districts. It has not given any tally of civilian deaths, and it's unclear how it is separating noncombatants killed from militants.

Residents fleeing the region have reported dozens of ordinary Pakistanis killed in the fight.

Some 1,500 to 2,000 hard-core insurgent fighters remain in Swat, the army says. Information provided by the military and civilians is nearly impossible to verify independently because of limited access to the area.

The army said it could take at least another week to remove insurgents from Mingora.

With files from The Associated Press