According to AFP, a lone suicide bomber blew himself up after he was confronted by the mosque security guard as he tried to enter the complex during evening prayers, officials said.
The guard and one other person died, as well as the bomber. The police spokesman said that suicide vest was faulty and did not detonate completely.
“The security guard tried to stop the suicide bomber and he unsuccessfully tried to blow himself up however he was not able to detonate his suicide vest properly,” he said.
The Imambargah Qasr-e-Sakina is located at Islamabad Expressway.
Dr Ayesha Esani of Pakistan Institute of Medical Sciences (PIMS) told media that three people had died who were brought to hospital. Two of them were identified as Ghulam Hussain and Abdul Shakoor, she informed.
The attack is the latest in a wave of deadly sectarian attacks. In January 61 people were killed in a suicide bombing carried out by a Taliban splinter group at a Shiite mosque, the deadliest sectarian incident to hit the country in nearly two years.
At least 23 people were killed in another attack on a Shiite mosque in northwest Pakistan last week, claimed by the Taliban.