LAHORE: Militants unleashed coordinated attacks on Pakistani police Thursday, storming offices in Lahore and bombing a northwest station, killing 21 people and escalating 11 days of carnage.

The sophisticated assaults underscored the weakness of security forces seemingly unable to stop thwart high-profile attacks in the heart of Pakistan despite promises of a new offensive against the Talibannear the Afghan border.

Nuclear-armed Pakistan, which borders Afghanistan and is a key ally in the US-led fight against terrorism, is reeling from Taliban-linked attacks that have now killed at least 144 people since October 5.

More than 20 gunmen stormed a police commando academy in Bedian, on the outskirts of Lahore, another police school in the suburb of Manawan and the city branch of the Federal Investigation Agency(FIA).

Police said five attackers died in the attacks around Lahore, Pakistan's cultural hub, and that they were investigating reports that women were among the assailants, who were armed with guns and explosives.

"Four terrorists were killed in Manawan. One was hit by security forces and three blew themselves up," said Lahore city police chief Pervez Rathor.

At the FIA building, Rathor said, "one terrorist was killed and six security officials".

Police said the raids on the FIA premises and Manawan building -- which were the target of previous attacks -- were repelled.

But exchanges of fire continued at Bedian where helicopters circled overhead, and there were media reports of hostages.

"In Bedian the situation is not clear. There are initial reports that eight to 10 people climbed up the wall from behind... There are reports that the attackers included three women but it is not yet fully confirmed," said Rathor.

Pakistan's weak civilian government said the country was facing a new war after a slew of militant attacks in the country's political heartland of Punjab, away from the hotbed of insurgency in the northwest tribal region. Chronology: 11-days of bloodshed

"They are involved in guerrilla war. First they were active in NWFP (North West Frontier Province), now they are engaged in Punjab. They are terrorists paid to destabilise Pakistan," Interior Minister Rehman Malik told reporters.

US President Barack Obama is poised to sign a bill giving 7.5 billion dollars to build schools, roads and democratic institutions in Pakistan as part of a strategy to discredit extremists in the nation and inAfghanistan. Related article: US aid

Thursday's attacks underscored poor police security. The training centre at Manawan was attacked on March 30. Eight police recruits died before security forces finally overpowered the multi-pronged assault after nearly eight hours.

The FIA building in Lahore was bombed in March 2008, killing 16 people.

In the northwest town of Kohat near Peshawar, regional police chief Abdullah Khan said 10 people were killed.

"It was a van suicide attack," Khan told AFP. Police said the bomber rammed his vehicle into the outer wall of the police station in Kohat and that the building was badly damaged.

Tens of thousands of people have fled the lawless tribal region ahead of an expected army offensive, where warplanes are pounding Taliban positions and a US missile strike killed the head of the Pakistani Taliban in August.

At least 52 civilians were killed on Friday last week when a suicide bomber blew up his car in a packed market in Peshawar.

The following day, Taliban-linked gunmen staged an audacious raid on army headquarters near Islamabad with 23 people killed in a day-long siege that also saw 39 hostages freed by commando troops.

After the militants' brazen headquarters assault, speculation has intensified that the military is preparing to go into the militant stronghold of South Warizistan, months after the government promised a ground operation.

On Thursday, a US drone missile attack on a suspected militant hideout in remote North Waziristan killed at least four people, security officials said. Related article: US drone attack in Pakistan

The pre-dawn strike targeted the suspected militant compound in Dandey Darpa Khel near the Afghan border, a security official said.