The blast occurred inside the mosque in the Police Lines area around 1.40 pm when worshippers, which included personnel of the police, army and bomb disposal squad, the officials said.
A Taliban suicide bomber blew himself up in a mosque packed with worshippers during afternoon prayers on Monday in the high-security zone in Pakistan's northwestern Peshawar city, killing at least 46 people and wounding more than 100 others, mostly policemen, security and health officials said.
The blast occurred inside the mosque in the Police Lines area around 1.40 pm when worshippers, which included personnel of the police, army and bomb disposal squad - were offering the Zuhr (afternoon) prayers. The bomber who was present in the front row blew himself up, officials said.
Lady Reading Hospital officials said 46 people have died so far. However, the Peshawar Police has released a list of 38 victims.
There were mostly policemen among the injured.
A brother of the slain commander of the Tehreek-e-Taliban Pakistan (TTP) Umar Khalid Khurasani claimed that the suicide attack was part of the revenge attack for his brother who was killed last August in Afghanistan.
The outlawed TTP, known as the Pakistani Taliban, has carried out a number of suicide attacks in the past, targeting security personnel.
Superintendent of Police (Investigation), Peshawar, Shazad Kaukab, whose office is close to the mosque, told the media that the blast occurred when he just entered the mosque to offer prayers. He said he luckily survived the attack.
A police official said that a portion of the mosque collapsed and several people were believed to be under it.
The bomber entered the highly secured mosque inside police lines where four layers of security were in place to enter the mosque.
Quoting Capital City Police Officer (CCPO) Peshawar Muhammad Ijaz Khan, Dawn newspaper said that a number of jawans are still stuck under the rubble and rescuers are trying to pull them out.
Khan said between 300 to 400 police officials were present in the area at the time of the blast. "It is apparent that a security lapse occurred," he told the media.
Prime Minister Shehbaz Sharif strongly condemned the attack, saying the attackers behind the incident "have nothing to do with Islam”.
“Terrorists want to create fear by targeting those who perform the duty of defending Pakistan,” he said and vowed that the sacrifices of the blast victims will not go in vain. “The entire nation is standing united against the menace of terrorism."
He also said that a comprehensive strategy will be adopted to counter the deteriorating law and order situation in restive Khyber Pakhtunkhwa and the federal government will help provinces in increasing their anti-terrorism capacity.
Foreign Minister Bilawal Bhutto Zardari also condemned the attack, saying "terrorist incidents before the local and general elections were meaningful".
Khyber Pakhtunkhwa Governor Haji Ghulam Ali condemned the blast and urged the people to donate blood for the injured, saying that it would be a "huge favour for the police”.
The injured are being shifted to the Lady Reading Hospital, officials said.
Hospital sources said 13 of those injured were in a critical condition.
An emergency has been declared in the hospitals of Peshawar. The hospital has appealed citizens to donate blood for the victims.
Security has been beefed up in other major cities, including Islamabad, after the Peshawar blast. In Islamabad, security at all entry and exit points of the capital city has been increased and snipers have been deployed at "important points and buildings".
Caretaker Chief Minister Azam Khan condemned the attack and offered condolences to the bereaved families.
Former prime minister Imran Khan strongly condemned the terrorist attack in the mosque.
"My prayers and condolences go to victims' families. It is imperative we improve our intelligence gathering & properly equip our police forces to combat the growing threat of terrorism," the Pakistan Tehreek-e-Insaf tweeted.
Last year, a similar attack inside a Shia mosque in the Kocha Risaldar area in the city killed 63 people.
The TTP, set up as an umbrella group of several militant outfits in 2007, called off a ceasefire with the federal government and ordered its militants to stage terrorist attacks across the country.
The group, which is believed to be close to al-Qaeda, has been blamed for several deadly attacks across Pakistan, including an attack on army headquarters in 2009, assaults on military bases, and the 2008 bombing of the Marriott Hotel in Islamabad.
In 2014, the Pakistani Taliban stormed the Army Public School (APS) in the northwestern city of Peshawar, killing at least 150 people, including 131 students. The attack sent shockwaves across the world and was widely condemned.