Updated 7.40am

A blast at one of Pakistan's oldest and most popular Sufi shrines killed at least four people and wounded 24 in the eastern city of Lahore Wednesday, police said, as the country marks the fasting month of Ramadan.

Police have said they are still investigating the nature of the blast, which occurred near the entrance gate for female visitors to the 11th century Data Darbar shrine, one of the largest Sufi shrines in South Asia, the channel and police said.

The shrine has been targeted previously, in a 2010 suicide attack that killed more than 40 people, and is guarded by heavy security.

Sufi worshippers, who follow a mystical strain of Islam, have frequently been the target of bloody attacks by Islamist militants including the Islamic State group in Pakistan.

Militant Islamists see visits to Sufi shrines and some rituals at the graves of Muslim saints as un-Islamic.

Police in the eastern city confirmed that a blast had taken place but did not immediately give a toll. PTV aired footage showing damaged vehicles and emergency personnel on the scene.

A local police official, Muhammad Kashif, said the blast may have been "a suicide attack targeting security officials' vehicle".  

"We are trying to get more details from the site," he added.

A second police official who spoke on condition of anonymity also said that a security vehicle had been targeted in the blast. 

Pakistan's push against extremism was stepped up after the country's deadliest ever attack, an assault on a school in Peshawar in 2014 that left more than 150 people dead - mostly children.

Since then, security has dramatically improved - but militants retain the ability to carry out dramatic attacks.

Major urban centres such as Lahore, Pakistan's second largest city and the provincial capital of its wealthiest province, Punjab, are not immune. 

An attack in Lahore in March last year left nine people dead, while a major blast targeting Christians celebrating Easter in a park in 2016 killed more than 70 people.

Critics have long argued the military and government crackdown does not address the root causes of extremism.

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.