An alliance of Pakistani Islamic schools vowed Wednesday not to hand over five foreign students with expired visas for deportation amid government efforts to crack down on madrassas accused of promoting religious extremism.

Pakistan has ordered hundreds of foreign students at local seminaries to leave after it emerged that one of last year's London transit system bombers had visited a madrassa linked to an outlawed militant group.

Authorities want to deport three Malaysians, one Indonesian and a Sri Lankan attending the Jamia Islamiya seminary in the southern port city of Karachi, said school official Qari Mohammed Iqbal.

The students' visas expired earlier this year and the seminary applied to extend permission for them to remain in Pakistan, but the request was rejected, Iqbal said.

"All foreign students in our seminaries have legal status here and we are not going to allow anybody to expel any of them," said Mohammed Hanif Jalandari, a representative of an influential alliance of the religious schools.

About 100 foreign students at the Jamia Islamiya seminary have left Pakistan since the government announced plans to expel any without valid visas, Iqbal said. No new applications for students to attend his madrassa have been lodged in recent months.

Jalandari said he and other officials had met with Pakistani President Gen.Pervez Musharraf this year to discuss plans to let the students stay.

Government officials were not immediately available for comment.

The move by the seminaries comes a day after police identified the suicide bomber who killed a prominent Shiite cleric on July 21 in Karachi as 16-year-old of Bangladeshi descent.

The purported bomber, Abdul Karim, attended Karachi's Jamia Kahlilia madrassa from 2003-2004, said school administrator Maulana Idress Muzahiri.

"At that time he (Karim) was a quite minor guy of 12 or 13 years of age and used to memorize his lessons quietly and without any trouble," said Muzahiri.

At least four people, including three suspected Sunni Muslim militants, have been detained in connection with the bombing. Karim's mother and brother are in custody assisting police inquiries.

More than 10,000 madrassas are estimated to be in operation in Pakistan, long considered a breeding grounds for militants.

Musharraf, a key U.S. ally in the war against terrorism, has accused some schools of "spawning hatred" and militancy and said Pakistan had cracked down on a number of madrassas in its tribal regions bordering Afghanistan that had harbored terrorists.

Pakistani authorities detained hundreds of people suspected of links with militant groups following the July 7 London bombings, including some preachers accused of spreading sectarianism and hatred. It also ordered more than 1,400 foreign students expelled.