Two suicide bombers struck worshippers at the grave site of one of the most revered Sufi saints [AFP]

Pakistani police have stepped up security in the southern city of Karachi in response to fresh unrest following a deadly attack on a busy Sufi shrine.

The country's largest city was mostly quiet early on Friday, a day after angry mobs burned tires and torched houses into the night.

The unrest came in the aftermath of the bombings at the Abdullah Shah Ghazi shrine in which two suspected suicide bombers killed at least eight people and wounded 65 others at the crowded site.

Meanwhile, authorities continued an investigation on Friday into the culprits behind Thursday's shrine attack.

Hallmarks of Taliban

The first explosion took place as the suspected bomber was going through a metal detector leading up to the shrine, Babar Khattak, the senior police official in Sindh province, said.

The second blast took place about 10 seconds later, farther ahead of the metal detector, he said.

The attack happened at the busiest time of the week when thousands of people typically visit the site to pray, distribute food to the poor and toss rose petals on the grave of the saint.

Al Jazeera's Sohail Rahman, reporting from the capital Islamabad, said the attack "has all the hallmarks of a Taliban assault".

"They feel, and have said many times in the past, that this [Sufi] form of Islam is un-Islamic and unacceptable to them."

Thursday's explosions echoed a twin suicide bombing at a well-known Sufi shrine in the eastern city of Lahore that left 40 people dead earlier this year.

Source: Al Jazeera and agencies