In the far northwest, a suicide bomber blew himself up at a police training centre in the city of Hangu, killing at least seven people.
The bomber tried to get into a police centre early on Thursday morning when young recruits were going in for training.
Fakhr-e-Alam, the city's chief administration official, said: "The attacker tried to crash through the gate. He blew himself up as security guards at the gate tried to stop him.
"Six policemen and a passerby were killed."
A police official said 13 people were wounded.
Tribal fighters in North Waziristan last week vowed to attack security forces after abandoning a 10-month peace pact with the government which it said the government violated.
At least 16 Pakistani soldiers were reported to have been killed one day before, in an ambush against a military convoy near the Afghan border.
And on Tuesday, a suicide bomb had killed 16 people and injured 86 others at a rally in support of the country's chief justice.
'State of emergency'
The spate of attacks prompted the government to consider imposing a state of emergency on Wednesday. But Pervez Musharraf, the Pakistani president, later ruled out declaring an emergency.
"The president was asked whether an emergency would be imposed because of the growing violence and the president clearly said it would not," said a senior government official, citing the president in talks with newspaper editors.
An emergency would mean the postponement of elections due around the end of the year. Musharraf has repeatedly said elections, including a bid by him for a second term, would be on time.