A minister in Pakistan's Balochistan province was assassinated by unidentified gunmen in the southwestern city of Quetta, police said.

Education Minister Shafiq Ahmed Khan, who belonged to the Pakistan People's Party, was on his way home after attending a function when gunmen opened fire at his vehicle.

Khan was killed instantly while one of his relatives was seriously injured in the attack. The Baloch United Liberation Front claimed responsibility for the killing.

The same group was involved in the kidnapping of a UN official earlier this year.

Witnesses said the gunmen fled from the area after the attack.

Police cordoned off the area and launched a search for the attackers. Reports said Khan was driving his own car and did not have any security guards at the time of the attack.

His aides said he had been receiving threats for some time from Baloch nationalist groups.

Balochistan has witnessed several attacks by these groups in the past few months, many of them targeting Punjabi and Pashtun people.

Prime Minister Yousuf Raza Gilani condemed the assassination of the provincial minister and ordered an inquiry into the incident.

He also directed authorities to arrest the killers.