Tens of thousands of mourners attended the funeral Thursday of a well-known Pakistani Sufi singer who was gunned down the day before in the port city of Karachi in an attack claimed by Islamic extremists.

Pakistani television footage showed tearful mourners throwing rose petals over an ambulance carrying the coffin of Amjad Sabri, whose car was ambushed by gunmen when he was on his way to a local TV appearance. Sabri was later buried at a local cemetery.

Sabri and his late father, Ghulam Farid Sabri, were renowned qawwali singers, a style of music rooted in Sufism, or Islamic mysticism.

Militants in Pakistan have targeted Sufis in the past and destroyed their shrines. On Wednesday, two attackers on a motorcycle opened fire on Sabri's car, killing him and wounding his brother who was also in the car.

A splinter faction of the Pakistani Taliban said after the attack that it had killed Sabri because he was a "blasphemer."

In 2014, a blasphemy case was filed against a local TV station in Pakistan after it aired a show in which Sabri sang a qawwali that made reference to historic religious figures. The case has been pending in court.

Karachi has long been gripped by violence, with attacks carried out by Islamic militants as well as ethnic separatists, criminal gangs and rival political parties. Pakistani Prime Minister Nawaz Sharif has condemned Sabri's killing and ordered an investigation.