Pakistani police say a bomb has exploded at the main gate of a government-run hospital in the southwestern city of Quetta, killing at least six people.

Police official Afzal Khan says several people were also wounded in Monday's blast, which took place shortly after the body of a prominent lawyer killed in a shooting attack earlier in the day was brought to the hospital.

Khan says dozens of lawyers and journalists were present inside the hospital when the bomb went off. No one immediately claimed responsibility for the attack.

Anwalullah Kakar, the government spokesman in southwestern Baluchistan province, says an investigation is underway.

It was also unknown who was behind the killing of the lawyer, Bilal Kasi, who was gunned down on his way to court earlier in the day.