At least two people have been killed in a bomb blast in a popular shopping district in the Pakistani city of Lahore.

22 others were injured in the attack in the metropolis, the police said on Thursday.

The separatist group Baloch Nationalist Army from the southwest of the country claimed responsibility for the attack on Twitter.

The target was "bank employees," the group said.

A nine-year-old child was among the dead, police and rescue workers said.

The explosion happened in the Anarkali shopping district.

Several motorcycles were damaged and market stalls were knocked over.

"According to initial investigations, a timed explosive device on a motorcycle caused the explosion," police spokesman Rana Arif told AFP.

Pakistan's Prime Minister Imran Khan was dismayed at the "loss of precious human life," his spokesman said. 

Rebels from Balochistan, the largest and poorest of Pakistan's four provinces, have been carrying out attacks again and again for years.

They accuse the government in Islamabad of giving them too little of the income from Balochistan's natural resources.