Lahore, Pakistan: Pakistanis Tuesday mourned the victims of a Taliban-claimed suicide bomb in Lahore which killed more than a dozen people as the city's residents railed at the government for failing to protect them.

The chief minister of Punjab province Shahbaz Sharif declared a day of mourning after Monday's blast, believed to be targeting police managing a busy protest at rush hour on Mall Road, one of Lahore's main arteries.

At least 13 people were killed, emergency official Ahmad Raza told AFP, including six police officers, while more than 80 were injured. Earlier Tuesday he had put the death toll at 15, but said later that was a clerical error.

The toll could have been higher, Raza said, but for two vehicles -- a TV news van and a minivan belonging to the protesters -- which absorbed much of the impact of the blast.

Funerals were held Tuesday for some of the victims.

The Pakistani Taliban faction Jamaat-ul-Ahrar, which has vowed to attack government installations around the country, claimed responsibility for the assault.

The attack underscored the challenges faced by Pakistan in its push to stamp out militancy, even though security dramatically improved in 2015 and 2016.

Homegrown groups like the umbrella Tehreek-i-Taliban Pakistan (TTP) retain the ability to carry out spectacular assaults, despite a military-led crackdown on extremism.

Lahore residents vented their fury at the blast site early Tuesday.

"They (the militants) have no link with Islam nor do they believe in any religion, the only thing they know is killing people, this is utterly an act of terrorism," Tariq Saleem told AFP.

Nadeem Akhter called on the government to do more to bring the situation under control. "Our children and people are being killed in these attacks," he said.  

Both the UK and the US branded the attack "cowardly" in separate statements, while the EU said it was "shocked and saddened" by the incident.

Lahore, the country's cultural capital, suffered one of Pakistan's deadliest attacks in 2016 -- a Jamaat-ul-Ahrar suicide bomb in a park last Easter that killed more than 70 including many children.

But such incidents have been rare in the city in recent years.

Cricket fans had been quick to voice fears that Monday's explosion could derail plans to hold the highly anticipated final of the Pakistan Super League in Lahore.

Pakistan's international tournaments have been held abroad for years out of security fears, and the second year of the popular Twenty20 tournament is ongoing in the United Arab Emirates. 

Officials had already reassured international players they would receive "head of state" level protection in Lahore, with thousands of police deployed and bullet-proof buses.

"Now... there will be a wave of suspicion and fear in their minds," a frustrated PSL chairman Najam Sethi said on private TV channel Geo after the attack.

But he insisted Pakistanis show they are not afraid. "We will stand firm, we will fight... we will show you by having the final in Lahore."