Pakistan's government has pledged to take targeted action against militants, a day after a suicide bomb killed 53 people in the capital, Islamabad, BBC reported.
Interior Ministry adviser Rehman Malik said raids would be carried out in some "hotspots" near the Afghan border.
Earlier, the authorities revealed that a truck laden with 600kg of high-grade explosives had rammed the Marriott Hotel security gate before blowing up.
Rescuers have been combing the wreckage for survivors and bodies.
The blast left 266 people with injuries.
Although most of those killed were Pakistani, the Czech ambassador and two US defence department workers were among the dead.
A Vietnamese citizen was also killed in the blast, in which at least a dozen foreign nationals were wounded.
The Danish Foreign Ministry said one of its diplomats was missing.
No group has taken responsibility for the attack, but Mr Malik suggested responsibility lay with al-Qaeda and Taleban militants based in the Federally Administered Tribal Areas (Fata) on the Afghan border.
"In previous attacks, all roads led to Fata," he said.
The BBC's Barbara Plett, in Islamabad, says the attack might have been retaliation for army bombardments of suspected Taleban targets with jet fighters.
The heavily-guarded hotel was attacked at about 2000 (1500 GMT) on Saturday.
CCTV footage of the moments before the blast show a six-wheeler lorry ramming the security barrier at the hotel gate.
Shots are fired and the vehicle starts to burn. Security guards initially scatter, but return to try to douse the flames.
The footage breaks off at the moment of the blast because the camera was destroyed. It created a crater about 8m (27ft) deep, and triggered a fire which engulfed the 290-room, five-storey building for hours.
Officials said the lorry contained explosives as well as grenades and mortars. Aluminium powder was used to accelerate the explosion and added to the ferocity of the blaze.
"I do not believe this is a breakdown in security. The attackers had disguised the truck well as it was covered with a tarpaulin and loaded with bricks and gravel," Mr Malik said.
Witnesses described a scene of horror as blood-covered victims were pulled from the wreckage and guests and staff ran for cover from shattered glass and flames.
The fire has now burned out and rescue workers have been searching the building room-by-room, pulling bodies out of the blackened debris.
Immediately after the bombing, newly-elected President Asif Ali Zardari vowed to root out the "cancer" of terrorism in Pakistan.
He has now flown to New York to attend the UN General Assembly session, where he will meet US President George W Bush on the sidelines.
The meeting comes amid tension between the two countries over US attacks on militants in tribal areas of Pakistan, close to the Afghan border.
In the wake of the attack, President Bush pledged assistance to Pakistan in "confronting this threat and bringing the perpetrators to justice".
The Marriott is the most prestigious hotel in the capital, and is located near government buildings and diplomatic missions. It is popular with foreigners and the Pakistani elite.
The hotel has previously been the target of militants. Last year a suicide bomber killed himself and one other in an attack at the hotel.