At least 47 people have been killed and tens of others wounded after unidentified armed men launched an attack on a bus carrying Shia Muslim pilgrims in Pakistan's southern province of Sindh.

At least 47 people have been killed and 24 others wounded in an attack during which unidentified armed men launched an attack on a bus carrying Shia Muslim pilgrims in Pakistan’s southern province of Sindh.

A senior police official, requesting anonymity, said the incident took place in the Safoora Chowk area of Karachi, located 1,146 kilometers (712 miles) east of the capital, Islamabad, on Wednesday, when a group of around eight assailants stopped the bus and opened indiscriminate fire on passengers.

Medical sources, also speaking on condition of anonymity, said among the victims were 25 men and 16 women.

Television networks on Tuesday carried pictures of a bullet-riddled pink bus.

Five of the injured victims succumbed to their wounds while en route to hospital. Some of the wounded people are reportedly in a critical condition, and the death toll is expected to rise, according to sources.

Tehreek-i-Taliban (TTP) has reportedly claimed responsibility for the attack.

On March 20, gunmen fatally shot Shia religious leader Mazahir Naqvi, also known as Pyare Sahab, in the town of Gujranwala, located some 200 kilometers (120 miles) southeast of Islamabad. Naqvi died on the spot, and the assailants fled the scene.

A total of 22 people were also killed in a gun-and-bomb attack on a Shia mosque packed with worshipers in the northeastern city of Peshawar on February 13.