The brazen early morning attacks in Rawalpindi coincided with the announcement that Nawaz Sharif, a former prime minister overthrown in 1999 by the country's current military leader Gen. Pervez Musharraf, would return from exile Sunday.

Sharif, one of Musharraf's most strident political foes, may contest parliamentary elections scheduled for January.

"Nawaz Sharif and other members of his family are coming back to (the eastern Pakistani city of) Lahore on Sunday," said Sadique al-Farooq, a senior leader of Sharif's Pakistan Muslim League-N party.

The suicide attacks came as Pakistan remained under a state of emergency, which Musharraf declared on Nov. 3, justifying it by citing the escalating danger posed by Islamic extremists. His critics have noted, however, that many of his moves have been against political opponents - including members of the judiciary, journalists and other moderates.

The two suicide attackers struck just before 8 a.m. in Rawalpindi, a garrison city just south of the capital, Islamabad, as employees were arriving for work.

In the first attack, an explosive-laden car rammed a bus carrying employees from the Inter-Services Intelligence agency, or ISI. The other bomber hit an army checkpoint in another part of the city, said Mohammed Afzal, a local police official.

Two senior intelligence officials - one of them at the scene - said at least 35 people were killed. They requested anonymity, citing the sensitivity of their work.

An army statement said it could only confirm that 15 were killed in the attack on the bus, as well as the suicide bomber. It said that two security forces personnel were critically injured in the second attack, and that the bomber died.

"We suspect that pro-Taliban militants who are fighting security forces in our tribal areas are behind this attack," one intelligence official said, adding the injured and dead were being transported to hospitals.

The other intelligence agent, who was at the scene, said that the destroyed bus was a 72-seater, but that it was badly overloaded and more people were believed on board. The army statement said 50 were on the vehicle.

After the blast, troops and police quickly cordoned off the area. They pushed people back and snatched cameras and mobile phones from journalists and bystanders. Agents fanned out across the area, picking up pieces of metal that appeared to be from the bomber's car.

Shoaib Abbasi, owner of the Oriel guesthouse across from the intelligence compound, said that when he came out on the street after the blast, the bus was burning fiercely.

"Firemen tried to open the emergency doors while they were dousing the interior, but I can't believe anyone inside survived because of the intensity of the fire," he said.

Khyzer Hayat, the owner of a nearby grocery store, said the blast occurred at 7:40 a.m. "After the explosion, I went out on the street and found the ignition switch for a car amid the debris (which) I later gave to an intelligence agent," he said.

Musharraf condemned the blasts and sent his condolences to victims' families. He said the attacks would not deter his government's resolve in fighting terrorism, according to Pakistan's state news agency.