ISLAMABAD, Pakistan (AP)- Pakistani security agents raided a home near the capital of Islamabad and arrested the head of an al-Qaeda linked outlawed militant group accused of killing hundreds of minority Shiites, a security official said Wednesday.

Asif Chotto, the reputed head of Lashkar-e-Jhangvi, was captured with other suspects in Rawalpindi, a garrison city near Islamabad, said the official, who spoke on condition of anonymity because he is not authorized to speak to the media.

Chotto is believed to have masterminded major attacks against Shiites in recent years.

Although Interior Minister Aftab Khan Sherpao refused to confirm or deny the arrest, another intelligence official said Chotto was in the custody of a Pakistani spy agency and was being questioned. &#34He is a major catch. We were looking for him for the past three years,&#34 said the official, who also did not want to be named because he is not authorized to discuss cases with reporters.

The official gave no further details other than to say that Chotto was involved in several bomb attacks against Shiites in the southern city of Karachi, the eastern city of Lahore and Sialkot and elsewhere.

Farooq Awan, a police investigator in Karachi, who has been involved in the arrests and interrogations of Lashkar-e-Jhangvi”s men, said he knew about Chotto”s arrest through the media, and that he had not been officially informed about it. However, he said Chotto began leading Lashkar-e-Jhangvi in 2002 after its chief, Akram Lahori, was arrested.

&#34Chotto is a very dangerous person. He was involved in all major attacks against Shiites in Karachi,&#34 Awan said.

According to Pakistan”s independent Geo television, Chotto was planning new attacks when he was captured in Rawalpindi. It said authorities had detained some of his associates from various parts of the eastern Punjab province.

Pakistan has a history of sectarian violence, mostly blamed on rival majority Sunni and minority Shiite extremist groups.

Although most of Pakistan”s Sunni and Shiite Muslims live peacefully together, small radical groups on both sides often target each other”s leaders and activists. About 97 percent of Pakistan”s 150 million population is Muslim, and Sunnis outnumber Shiites by a ratio of about 8-to-2.

The schism between Sunnis and Shiites dates back to the 7th century and involves a dispute over who was the true heir to the prophet Muhammad.