Photo: Alamy

A suicide attack in a popular shrine in southern Pakistan has killed at least 72 people, police say, the BBC reports.

The bomber blew himself up among devotees in the shrine of Sufi saint Lal Shahbaz Qalandar in the town of Sehwan in Sindh province, police said.

Prime Minister Nawaz Sharif has condemned the attack, which has been claimed by so-called Islamic State.

It is the deadliest in a string of recent bombings claimed by IS, the Pakistani Taliban and other militants.

The shrine, one of the country’s oldest and most revered, was crowded as Thursday is considered a sacred day for Muslims to pray there.