KARACHI, Pakistan — Gunmen killed two people returning from a funeral Monday for Shi’ite Muslim victims of a massive bombing that killed 48 people in Karachi, highlighting escalating sectarian tensions.
The bomb exploded Sunday evening as people were leaving a mosque and underlined the increasing threat Shi’ites face as Sunni militant groups target them in ever-bolder attacks. There was no immediate claim of responsibility but Sunni militant groups who do not consider Shi’ites to be true Muslims have previously carried out such attacks.
Thousands of Shi’ite Muslims turned out Monday to bury their dead and demanded government protection from militant groups.
Some of those attending the funeral set fire to buses in one Karachi neighborhood as they went to the cemetery, said police official Qamar Ahmad.
When they moved through the same area after the funeral, gunmen opened fire on the group and wounded several protesters, he said.
Two of the men died and 13 were wounded, said Dr. Saleem Memon, who works at a nearby hospital.
Thousands of people thronged a main road in Karachi on Monday for the funeral service. Many beat their chests and heads and chanted ‘‘Stop the brutal attacks!’’ They called on the government to take action against groups responsible for the attacks.
‘‘Terrorists are killing us everywhere, but the state is nowhere to be seen,’’ said Intizar Hussain, whose father died in the bombing.
It was the third mass-casualty attack since the beginning of the year against Shi’ites. The first two killed nearly 200 people in the southwestern city of Quetta. Lashkar-e-Jhangvi, a Sunni group known for its virulent hatred of Shi’ites, claimed responsibility for the two attacks.