Gunmen have shot dead a senior judge in Pakistan’s garrison city of Rawalpindi, not far from the capital, Islamabad, security sources say.

Local Pakistani security officials said three assailants on motorbikes opened fire on Tahir Khan Niazi, as he was leaving his residence in Sadiqabad area of Rawalpindi, located in the northern part of Punjab Province, on Wednesday.

The sources said Niazi, was rushed to a nearby hospital with fatal injuries following the assault but he succumbed to his wounds later in the hospital.

A large number of lawyers gathered outside the hospital after receiving the news.

Local media reports said the assailants managed to flee the scene before security sources arrived. Pakistani security forces have launched a massive manhunt across the region to arrest the attackers.

There has been no claim of responsibility for the killing, but pro-Taliban militant groups in Pakistan have been blamed for such attacks in the past.

The militants have repeatedly issued threats against those judges who have reputation for grilling detained Taliban militants at anti-terrorism courts across the country. 

In July 2013, pro-Taliban militants claimed responsibility for a violent deadly bomb attack that targeted a convoy of senior judicial officials in the southern port city of Karachi. The banned Tehrik-i-Taliban Pakistan (TTP) said at the time that senior judges were targeted for "anti-Taliban decisions" in recent years.