A fire killed 67 prisoners when it swept through a jail near the Saudi capital Riyadh Monday, but officials said it was too early to say what caused the blaze, the official Saudi Press Agency (SPA) reported.

SPA quoted the head of prison affairs at the Interior Ministry as saying 20 inmates and three security guards were injured in the blaze which broke out at around noon.

It was not immediately known if the prison housed any of the more than 200 Islamic militants arrested in recent months in a nationwide hunt for supporters of Saudi-born Osama bin Laden's al Qaeda network.

"It is too early to tell whether the fire is an act of sabotage but an investigation is going on," a Saudi security source told Reuters in Dubai.

By evening, the fire appeared to be extinguished and no smoke was visible outside the Hayer prison, 25 miles south of the capital, witnesses said.

Relatives of prisoners crowded a road leading to the large prison complex trying to find out about their loved ones, the witnesses said.

Saudi television showed footage of police officials visiting the blackened cell blocks. Some parts of the prison were cordoned off, apparently before the arrival of forensic and fire investigators.

Interior Minister Prince Nayef bin Abdul-Aziz ordered a committee to be set up to investigate the cause of the fire.

Saudi Arabia intensified its campaign against militants after May bombings in Riyadh that killed 35 people, including nine Americans.

The manhunt has led to several bloody clashes with militants and the seizure of large arms caches.

The United States has stepped up pressure on its key regional ally to crack down on militants and reform its powerful religious establishment, which the West says breeds hatred toward Christians and Jews.

In March last year, 15 schoolgirls died and at least 50 were injured in a stampede after fire broke out at their secondary school in the Muslim holy city of Mecca.

The disaster caused uproar in the kingdom, students' relatives blaming the education ministry for inadequate safety procedures and overcrowding.

Saudi newspapers said that all the casualties occurred in the rush to get out of the three-story building, some girls throwing themselves out of windows while others were trampled to death on the stairs.

(China Daily September 16, 2003)