A doctor was shot dead in Manghopir neighbourhood in western district and another was gunned down around noon at Tariq Road in the eastern part of the city.

They were identified by police as Dr Sher Ali and Dr Naseem Zaidi.

"The killing pattern shows that they were apparently carried out on sectarian grounds," Javed Alam Odho, the deputy inspector general of police said.

The other two victims were killed in central district when unknown attackers burst into a tailor's shop and opened fire.

The owner and a worker were killed and three others were injured.

"The attack seemed to be on sectarian lines as all of the people inside the shop were Shias," senior police officer Aamir Farooqi said.

Four other Shia Muslims were killed by gunmen on Sunday.

The latest attacks came ahead of the beginning of the Muslim holy month of Moharram, when Shias mourn the martyrdom of Imam Hussain, the grandson of Prophet Muhammad, along with his family members.

Police are already carrying out operations against criminal groups to curb sectarian and political killings.

Security would be further tightened in the month of Moharram, they said.

RA/NJF