Police say the death toll in a twin suicide bombing in Pakistan's Lahore city has risen to 39 and that nearly 100 others have been wounded.

Pakistan interrogated suspects and stepped up security Friday in a bid to prevent further bloodshed after a series of attacks blamed on Islamist militants left 160 people dead in 11 days.

A wave of violence in the past two weeks has killed more than 150 people in Pakistan and fueled concerns that the Taliban had linked up with other militant groups around the country.

A Pakistani Taliban group has claimed responsibility for the suicide bombing of a Lahore police building that killed 30 and wounded 250 people, a US specialist Islamist monitoring group said.

UN Secretary-General Ban Ki-moon has strongly condemned the terrorist bombing on an office of Pakistan's spy agency ISI in Lahore, saying no cause can justify such "indiscriminate violence".

Condemning the blast in Lahore, External Affairs Minister S M Krishna on Wednesday hoped that Islamabad and New Delhi can join hands to fight "this spectre of terror."

Pakistan's Interior Minister Rehman Malik on Wednesday pointed the finger at the Taliban for the daring suicide attack on the ISI provincial headquarters in the eastern city of Lahore and warned the authorities won't be deterred and would press hard with their current campaign.

Gunmen detonated a car bomb near police and intelligence agency offices in Lahore on Wednesday, killing about 30 people and wounding more than 100 in one of Pakistan's deadliest attacks this year, officials said.

Pakistani investigators have identified the 13 terrorists who attacked the Sri Lankan cricket team's motorcade here last month and made "enough progress" in their probe into the incident, a senior police official said on Tuesday.

"It is time that we all recognise that terrorism has roots across the region. A regional strategy therefore needs to be developed," Zardari told participants of a upcoming conference of Pakistani and Afghan parliamentarians, experts and editors in Islamabad on Monday night.

Pakistani Taliban chief Baitullah Mehsud on Monday claimed responsibility for the audacious terrorist attack on the police training centre in Lahore and warned that his group was planning to carry out an "amazing" attack on the US.

Terror struck Lahore for the second time in a month on Monday when heavily armed gunmen stormed a police academy, killing at least nine persons in an eight-hour siege that ended when all the attackers were captured or killed.

Attackers armed with guns and grenades stormed the police training ground near Pakistan's cultural capital Lahore in a brazen raid that mimicked the commando tactics used to attack the Sri Lankan cricket team four weeks ago.

Interior ministry chief Rehman Malik suggested home-grown terror movements were responsible, listing the groups Lashkar-e-Jhangvi, Lashkar-e-Taiba and Jaish-e-Mohammad.

Television footage also showed police and other security forces surrounding the bearded man and kicking him in a field outside the compound.

At least 20 people were killed Monday after gunmen stormed a Pakistan police training school near the eastern city of Lahore, police officials told AFP.