Peshawar: At least 19 people were killed and 60 others injured on Friday when seven militants attacked a Shi'ite mosque in northwest Pakistan.

The operation to flush out armed men from the mosque is said to be over now.

According to reports, one militant blew himself up inside the mosque in the capital of Khyber Pakhtunkhwa province.

Six-seven explosions reportedly took place inside the mosque at the time of prayers. Notably, around 1,000 people were present in the mosque at the time of the attack.

Senior police official Rana Umer Hayat told a news agency that several gunmen threw grenades before storming the Imamia mosque in Peshawar, the main city in Pakistan`s restive northwest.

Security and rescue operation teams have been dispatched to the site. Forces are cordoning off the site for further inspection.

The number of casualties is expected to increase.

TV footage showed people running away from the scene, some carrying injured on their shoulders, others limping, as police fired shots and checked people at a barrier.

An eyewitness was quoted as saying that Friday prayers were being offered at the mosque when five to six armed men wearing security forces` uniform entered the place of worship and hurled grenades at the security personnel deputed at the premises.

He added that one of the attackers, who was wearing a suicide vest, blew himself up inside the mosque after which the rest of his associates began indiscriminate firing.

Another eyewitness, Muhammad Raza, told a news agency: "There was a huge explosion, I can see many injured lying in front of me."

Pakistan Tehreek-e-Insaf chief Imran Khan was denied access to the site due to security reasons.

Meanwhile, a state of emergency has been imposed in Hayatabad Medical Complex. No group has claimed responsibility for the attack.

The mosque is close to several government buildings including the offices of the Federal Investigation Agency and passport agency.

Mushtaq Ghani, information minister for Khyber Pakhtunkhwa province, of which Peshawar is the capital, told Geo TV the attack was a response to the Army`s ongoing offensive against militants in the tribal areas along the Afghan border.

As per reports, Pakistan Taliban took the responsibility for the attack.

Since June last year, the Army has been waging a major campaign against strongholds of Taliban and other militants in the North Waziristan tribal area, which lies close to Peshawar.

The military has heralded the success of the operation, which it says has killed more than 2,000 militants, though the precise number and identity of those killed cannot be verified independently.

Pakistan has suffered a rising tide of sectarian violence in recent years, most of it perpetrated by hardline Sunni Muslim groups against minority Shi'ite Muslims, who make up around a fifth of the population.

The suicide bombing at a mosque in southern Sindh province on January 30 was the deadliest sectarian attack in Pakistan since February 2013, when 89 were killed in a market bombing in the southwestern city of Quetta.

Anti-Shi'ite attacks have been increasing in recent years in Karachi, Quetta, the northwestern area of Parachinar and the far-northeastern town of Gilgit.

The country has stepped up its fight against militants since a Taliban school massacre in Peshawar in December.

Heavily-armed gunmen went from room to room at the Army-run school gunning down more than 150 people, most of them children, in an attack that horrified the world.

(With Agency inputs)