Pakistani troops have arrested a man alleged to be the mastermind behind last month's Mumbai attacks.

Zaki-ur-Rehman Lakhvi is shown speaking at a rally in this June 2008 file photo. India alleges Lakhvi plotted last month's deadly Mumbai attacks. (Roshan Mughal/Associated Press) The troops seized a camp used by an extremist group close to the town of Muzaffarabad in the Pakistani part of the disputed Kashmir region on Sunday.

"It was our camp and our people were arrested from there," said Adullah Ghazanvi, spokesman for the banned group Lashkar-e-Taiba.

A senior intelligence official, who spoke on the condition of anonymity, told the Associated Press that 12 detainees were being questioned about possible links to the Mumbai attacks.

Another Pakistani official said Monday Zaki-ur-Rehman Lakhvi is among the detainees.

Lakhvi, an alleged militant, has been named by India as one of the main architects of the attacks in the country's financial capital. Indian officials allege Lakhvi recruited for the mission while Yusuf Muzammil, another militant, planned the operation.

U.S. officials said Lakhvi has also directed Laskhar-e-Taiba operations in Chechnya, Bosnia and Southeast Asia where he allegedly trained members to carry out suicide bombings.

A helicopter was used during the raid, and gunfire was exchanged, the official said. Several injured people are receiving treatment in a military hospital.

The identities of the other arrested militants were not released.

It is not immediately clear what Pakistan intends to do with Lakhvi, but it does not have an extradition treaty with India. Pakistani authorities did not formally announce the arrest of Lakhvi, a practice that is common there, especially in sensitive cases.

Pakistan previously indicated that anyone found on its soil to have connections with the Mumbai attacks will be punished according to its law, despite suggestions from India that it wants suspects in the attacks transferred to its custody.

Attacks killed 171

The Nov. 26 attacks by a group of gunmen on several central targets in the city, including two large hotels and a train station, killed 171 people and wounded 239. Among the dead were two Canadians.

This Nov. 26 photo shows Mohammed Ajmal Kasab at the Chhatrapathi Sivaji Terminal railway station in Mumbai. He was the lone gunman to survive the Mumbai attacks. (Mumbai Mirror/Sebastian D'souza/Associated Press)Militants told the Associated Press the camp where the raid took place had been used until 2004 by Lashkar-e-Taiba to train recruits to fight Indian rule in Kashmir.

More recently, the camp has been used by Lashkar's parent organization, Jamaat-ud-Dawa, for education and charity work, the unnamed militants said.

The sole surviving gunman in the attacks, Ajmal Amir Kasab, 21, has told interrogators he was sent by the Lashkar group.

Analysts have said Lashkar-e-Taiba was created with the help of Pakistan's intelligence agencies in the 1980s to act as a proxy fighting force in Indian Kashmir.

The New York Times, citing unidentified American intelligence and counterterrorism officials, published a story on Monday indicating Lashkar has gained strength in recent years with the help of Pakistan's spy service, the Directorate for Inter-Services Intelligence.

The officials cited by the Times said the Pakistani spy service has shared intelligence with and provided protection for the outlawed group.

However, there is no evidence to link the spy service to the Mumbai attacks, and the Pakistani government has denied any of its state agencies were involved in the Mumbai attacks and has pledged to co-operate with India.

U.S. and Indian suspicions that Pakistan-based militants carried out and plotted the attacks have sharply raised tensions between South Asia's only nuclear-armed nations.

U.S. Secretary of State Condoleezza Rice said Sunday there is "no doubt" the attacks were planned on Pakistani soil.

With files from the Associated Press