53 killed in Pakistan blast
The blast blew a vast crater in front of the building, which has been almost totally destroyed.
Senior police officials say it was a suicide attack involving a truck carrying more than 1,000 kilos of explosives.
The bombing on Saturday is one of the largest ever terrorist attacks in Pakistan.
The luxury Marriot Hotel is located close to many government buildings in the country's capital. Popular both with overseas business people and the Pakistani elite, it has been the target of attacks in the past.
One American was confirmed among the dead, as well as the Czech ambassador to Pakistan, who was staying in the hotel at the time. According to officials, another 20 foreigners are among the injured.
The bombing came just hours after the new President Asif Ali Zardari made his first address to Parliament.
Russia's President denounced what he called an act of barbarism and expressed solidarity with Pakistan's people.
Russia's nearby Trade Representative Office was partially damaged, and some of its suffered superficial injuries.
“The Russian Embassy and the building of the trade mission, located several hundred metres away from the blast site, suffered minor damage,” press attaché from the Russian embassy in Pakistan Aleksey Rykov told RT.
“The shock wave blasted out doors and windows. The embassy is establishing contact with Russian citizens currently staying in Pakistan. In general, the situation in Pakistan remains stable, with security measures tightened across the entire country,” he added.