Islamabad: The Czech ambassador to Pakistan was killed in Saturday’s deadly suicide attack at a hotel in Islamabad, Prime Minister Yousuf Raza Gilani said on Sunday.

At least 60 people were killed and nearly 250 wounded after a truck laden with explosives rammed into the gate of the Marriott Hotel on Saturday, triggering a huge explosion and fire.

"The Czech ambassador is among them (the dead). He has been identified," Gilani said, referring to diplomat Ivo Zdarek, who had been residing at the hotel at the time of the blast.

The Danish Foreign Ministry said a Danish diplomat was missing and one was wounded, while the Saudi ambassador said six Saudis were unaccounted for.

US and Pakistani intelligence officials said that the bombing bore the signs of an attack by Al Qaida or an affiliate.

The powerful bomb left a huge crater about 6 metres deep and 12 metres wide, at the hotel's main entrance.

Media reports cited unnamed police officials as saying that a group of 30 US marines, who were allegedly part of a security team for this week's visit by Admiral Mike Mullen, might be the intended targets for the attack.

The personnel were scheduled to leave for Afghanistan on Sunday, the Aaj television channel reported.

The attack came soon after Zardari made his first address to a joint session of parliament, pledging that Pakistan would not tolerate any infringement of its territory in the name of the fight against militants.

In a televised address on Sunday, Zardari condemned the attack as cowardly.

"This is an epidemic, a cancer in Pakistan which we will root out," he said. "We will not be afraid of these cowards."

Many of Islamabad's expatriate community were considering leaving, having shrugged off earlier attacks in the city, according to media reports on Sunday.