Islamabad, Jan 11 (IANS): At least 90 people were killed and over 260 injured Thursday in four blasts - three of them in Quetta - in Pakistan's Balochistan and Khyber-Pakhtunkhwa provinces Thursday.

At least 56 people, including a journalist and a senior police official, were killed and over 160 injured as two back-to-back bomb blasts hit Quetta in Balochistan province Thursday evening, Geo News reported. Twelve people were killed in the same city in an earlier blast.

There was a suicide attack at Rehmattullah Chowk late Thursday, followed by another blast in the nearby Airport road area minutes later, said police.

"The second bomb went off by the time rescue, media and law enforcement officials reached the spot," said sources.

Police officers, mediamen, and rescue workers were among the injured and the dead, said security sources. A senior police official put the number of those injured at 163.

Earlier in the day, at least 12 people, including two children and a security personal, were killed while 40 others sustained injuries after a powerful bomb, planted next to a paramilitary Frontier Corps checkpoint, ripped through Quetta' Bacha Khan Chowk area.

At least 22 people were killed and 65 injured in a blast in Khyber-Pakhtunkhwa province.

The blast, which was earlier perceived to be a cylinder blast, in Swat district was actually of an improvised explosive device, Geo News reported. Several of the wounded were in critical condition.