KARACHI (AFP) – A Saudi diplomat was killed in a hail of bullets on his way to the country's consulate in Karachi on Monday, the second attack on Saudi interests in Pakistan's biggest city in less than a week.

The Pakistani Taliban denied carrying out the assassination and authorities said they were investigating possible links to sectarian groups or the death of Saudi-born Osama bin Laden, who was killed by US Navy SEALs on May 2.

Saudi Arabia said the victim, Hasan al-Khatani, was travelling to work when he was killed and demanded that Pakistan tighten security measures for its diplomats, following a grenade attack on the mission building last week.

Police said Khatani worked in the consulate's security department and was driving a vehicle with diplomatic plates when two motorcycle riders unleashed a stream of gunfire at a crossroads in the city's upmarket Defence neighbourhood.

Karachi city police chief Iqbal Mahmood said militants fired four rounds, killing him at the scene, and fled on their motorcycle.