A roadside bomb hit a Pakistani security vehicle and wounded 13 people on Thursday in the southwestern Pakistani city of Quetta, days after a suicide bombing at a hospital killed at least 74 people, most of them lawyers, officials and media said.

Home Minister Safaraz Bugti said the homemade bomb targeted police personnel escorting a judge, who was not hurt in the attack, in the frontier city.

"It was a judge's car that was passing, but I believe it was the police who were the target," he said on Pakistani TV.

"It was a remote-controlled device with 3-4 kg of explosives ... I think these kinds of cowardly acts will not reduce our morale," Bugti said.

Medical Superintendent Abdul Rehman Miankhel told Reuters that 13 wounded people, including four members of the security forces, were being treated at the Civil Hospital, the same facility hit by Monday's suicide attack.

An announcer for Geo TV warned viewers not to gather at the scene on Zarghoon Road in central Quetta for fear of a second bombing like the one on Monday. That attack hit a large group of lawyers gathered at the hospital to mourn the head of the Baluchistan bar association who was shot dead earlier that day.

"Care must be taken that a rush not be created at the scene as the terrorists have reached the point of barbarity where they target crowds like this," the news announcer said.

Monday's hospital suicide bombing was Pakistan's deadliest attack this year. It was claimed by both a faction of the Pakistani Taliban, Jamaat-ur-Ahrar, and also by the Islamic State militant group, which has been seeking to recruit followers in Pakistan and Afghanistan.

Targeted killings have become increasingly common in Quetta, the capital of Baluchistan province that has seen rising violence linked to a separatist insurgency as well as sectarian tensions and rising crime.