Two successive bomb blasts have rocked the Pakistani garrison city of Rawalpindi, killing up to 16 people, police and military spokesmen have said.
The first blast on Tuesday happened on a bus carrying government workers. A motorcycle bomb exploded minutes later, killing at least four people.
Military and government officials said the bomb on the bus killed at least 12 people. It was believed to be carrying Pakistan Atomic Energy Commission employees.
"It's terrorism because innocent people were killed in both blasts," Major General Waheed Arshad, a military spokesman, said.
Bus destroyed
Mohammad Hamid, a police officer, confirmed it was a bomb that tore through the bus.
"The explosive was on the bus," said Javed Iqbal Cheema, an interior ministry spokesman.
The bus was completely destroyed and mutilated bodies lay on the street, a witness said.
Mohammed Afzal, an area police official, said the dead and injured had been transported to different hospitals.
There was no immediate claim of responsibility for either bombing.
Several retaliatory attacks have rocked Pakistan after the government of General Pervez Musharraf crushed an uprising by armed Islamic students at Islamabad's Red Mosque in July.