Claire Mackay reports at least 200 people are wounded.
The head of Pakistan's Interior Ministry Rehman Malik says it appears the suicide bomber intended to drive the truck laden with 600 kilograms of explosives into the foyer of the Marriott hotel.
Mr Malik says had that happened the building would have collapsed. Security footage shows the truck ramming security gates.
Failing to break through the suicide bomber blows himself up.
Moments later the footage cuts out at the time of the major blast.
It left a seven metre deep crater and the 300-room hotel was gutted by fire.
Rescuers couldn't reach many guests trapped on the upper floors and some jumped to their death.
The hotel was popular with diplomats the Czech ambassador is among the dead.
Australian assistance offer
No Australians were killed in the attack, but the foreign affairs minister, Stephen Smith, says Australia will offer whatever assistance it can to Pakistan in the wake of the terror attack on the Mariott Hotel.
Mr Smith says it was a brutal and cowardly attack that reflects the difficulties Pakistan is facing.
He's in New York for a meeting of the United Nations General Assembly, and says he'll hold talks with his Pakistani counterpart.
"Australia is ready willing and able to offer Pakistan whatever assistance it needs in terms of technical assistance and advice in meeting the terrorist threat that it faces and I'll be having that conversation with foreign minister Quereshi in the course of this week," he said.