ISLAMABAD, Pakistan (CNN) -- The Czech Republic's ambassador to Pakistan has been missing since a deadly blast Saturday night at the Marriott Hotel in Islamabad, the Czech News Agency reported.

Ivo Zdarek, 47, moved from Vietnam to Pakistan a month ago and was staying at the hotel, the national news agency said. It attributed its information to officials at the Czech foreign ministry.

He is married with two sons, according to the Web site of the Czech Embassy in Hanoi, where he was most recently posted.

The Czech Embassy would not confirm the report to CNN on Sunday.

The suicide truck bombing shook the heart of the capital city, killing dozens and wounding at least 200. It occurred at about 7:30 p.m. (9:30 a.m. ET), after the breaking of the fast during the holy month of Ramadan and the address by newly elected President Asif Zardari to a joint session of Parliament.

The Western hotel is located near the diplomatic section of the city near the compound that contains the parliament building, the prime minister's house, the Supreme Court and the presidency. The hotel is popular among tourists and was packed on Saturday night.

The Marriott, where a standard room costs more than $300 per night, has been the site of attacks in the past. Any vehicle entering the facility is searched and its underside checked for bombs before being allowed to pass through heavy steel gates.

Authorities received a threat two days ago, Pakistani Interior Minister Rehman Malik said. "We had taken all security measures," he said. "There was heavy security in the city."

Among the dead were two foreigners, Pakistan's Information Secretary told the Associated Press of Pakistan, which reported another 21 foreigners were wounded.

Initial casualty figures on the bombing were unclear and sometimes conflicting.

Police and government spokesman Farhatullah Babar said at least 40 people were dead, while Information Ministry spokesman Akram Shaheedi told APP Sunday that the death toll stood at 37, with 236 injured.

GEO TV's Hamid Mir, who was at the blast site, said he saw at least 52 bodies.

A spokesman for the Pakistan Institute of Medical Sciences, Dr. Wasim Khawaja, said the U.S. Embassy in Islamabad confirmed to him that an American was among the dead, and another was wounded.

A U.S. Embassy spokesman said all U.S. diplomats had been accounted for.

The British High Commission in Islamabad said four British nationals were being treated for wounds suffered in the blast. Two dependents of staff members were treated and released.

A spokeswoman for the German Foreign Ministry said that six Germans in the hotel were slightly hurt in the attack and that all embassy personnel were accounted for.

Most of the dead appeared to be drivers, who were waiting with their cars outside the Marriott, and hotel staff, most of them security guards, Geo TV's Mir said.

Mir said a witness reported seeing a small car ram open the hotel gates and then a truck carrying explosives, which detonated. "They were able to come right up to the hotel, close to the seat of power," Mir reported.

Initial reports indicated that an attacker or attackers drove a small truck with explosives through the hotel gate, Babar said. Police had earlier said it was a car bombing.

The hotel manager offered a different story, telling reporters the blast occurred outside the hotel's gates.

The explosion felled trees, and video showed a deep crater in the pavement where the bomb presumably detonated. More than a dozen cars were reduced to twisted steel.

CNN's Reza Sayah was inside a building more than two miles from the hotel when he felt the blast.
"It was a roaring rumble that would not stop. Seconds later, the windows shattered."