Pakistani security forces have raided a training camp used by Lashkar-e-Taiba (LeT), the militant group blamed for last month's attack on Mumbai, and arrested at least 12 of the group's activists, government officials said today.

One Pakistani official told The Times that among those arrested was Zakiur Rehman Lakhvi, LeT's operations chief, whom Indian officials have accused of masterminding the Mumbai attack.

The raid last night near Muzaffarabad, the capital of Pakistan-controlled Kashmir, was Pakistan's first attempt to respond to mounting pressure from India and the United States to take action against LeT after the Mumbai strike.

It is unlikely to satisfy either Delhi or Washington unless Islamabad follows up by prosecuting those arrested and taking further action against other militant groups linked to attacks on Indian soil.

"We've seen before how Pakistan will arrest some militants, keep them for a couple of months and then release them when the world's not paying attention," said B. Raman, a former head of the Pakistan desk at the Research and Analysis Wing (India's MI6).

"It must not be allowed to do that this time. They have to prosecute these people and dismantle the whole terrorist infrastructure," he told The Times.

Pakistani security officials refused to confirm or deny publicly the raid or the arrests of the activists from LeT, which is thought to have close links to Pakistan's poweful Inter-Services Intelligence agency. But government officials, speaking off the record, said that Pakistani troops raided a large compound belonging to Jamaat-ud-Dawa (JuD), the parent organisation of LeT, about three miles outside Muzaffarabad.

Local residents said that they saw army helicopters taking part in the raid and heard gunfire and explosions.

LeT was banned in Pakistan in 2002 after its militants attacked the Indian Parliament, prompting India and Pakistan to mass troops on their common border and almost sparking a fourth war between the nuclear-armed neighbours.

However, security analysts and officials said that LeT had continued to operate freely under the banner of JuD, which is led by LeT's founder, Hafiz Mohammed Saeed. Mr Saeed, who has denied any part in the Mumbai attacks, condemned yesterday's raid on his organisation's compound.

"The operation against jihadi organisations in Pakistani Kashmir is unwarranted and we strongly condemn it," he said. "The Government has shown signs of weakness by targeting Kashmiri organisations . . . India wants to crush the independence movement of Kashmir using the Mumbai attacks as a pretext."

Lakhvi, the alleged mastermind of the Mumbai attacks, was also a founder of LeT and has worked under several aliases as the group's supreme operational commander. US officials said that he had directed the group's operations in Kashmir, Chechnya, Bosnia and Iraq.

Also known as Abdullah Azam, he comes from Okara district in the central Pakistan province of Punjab, where Ajmal Amir Kasab, the only militant captured in the Mumbai attacks, was also born and raised.

Indian investigators said that Kasab had identified Lakhvi as one of his LeT contacts and admitted to undergoing training at several militant camps in Pakistan, including one near Muzaffarabad.

Yesterday's raid came only hours after Condoleezza Rice, the US Secretary of State, who visited India and Pakistan last week, urged Islamabad to act quickly and resolutely against those responsible for the Mumbai attacks.

Also yesterday, the Pakistani Government declined to comment on a report that it had agreed to a 48-hour deadline set by the US and India to to form a plan of action against LeT and hand over Pakistanis suspected of involvement in the Mumbai attack.

Top Pakistani civilian and military leaders are meeting in Islamabad today to discuss how to respond to the demands from India and the US. A senior Pakistani official told The Times that the crackdown against LeT and JuD could be extended to other areas of Pakistan.

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