Islamabad, Pakistan (CNN) -- Three explosions erupted Thursday in Lahore in and around one of Pakistan's holiest shrines, killing 50 people and wounding 175, according to police.
District Coordination Officer Sajjad Bhutta in Lahore described the casualty toll as he was touring hospitals where the wounded were being treated.
Lahore Commissioner Khusro Pervez said 25 of the wounded were in critical condition and that the remains of two suicide bombers -- a man in his 20s and another in his late teens -- were recovered after the blasts, which occurred at the Data Darbar shrine complex.
One of the bombers detonated in the shrine's courtyard; the other in the shrine's lower lever, he said. Two of the fatalities were women, he said.
The first explosion, which occurred at 10:48 p.m. (1:48 p.m. ET), was followed five minutes later by a second blast, Geo TV reported.
The CNN affiliate aired surveillance footage showing the first attacker entering through a gate holding a bag. As he passed through a metal detector, alarms went off and the man ran toward an area used for ablutions and blew himself up.
Geo TV showed a second attacker entering amid the confusion a few minutes later and running upstairs carrying a bag. Then the video showed the explosion.
The third blast occurred outside the shrine; the timing of the last blast was not clear.
Geo TV reported that the heads of two bombers were recovered and identified. The bombers had arrived at the shrine on foot wearing 10 kilogram (22 pound) jackets that had been packed with ball bearings, it said.
A witness told Geo TV that one of the bombers was wearing the traditional loose-fitting salwar kameez, a turban and slippers.
"This sickening poison of extremism will be driven out of our nation and we will not be cowed," said Farahnaz Ispahani, a spokeswoman for President Asif Ali Zardari, in a text message to CNN.
"Peaceful worshipers have once again been targeted by those who want to destroy the fabric of this great country. We will not forgive or forget and we will get justice for all Pakistanis murdered in cold blood -- be they Muslim, Christian, Ahmedi or of any other faith."
CNN's Nasir Habib, Nic Robertson, Nazneen Akbari, Thomas Evans, Katy Byron and Journalist Fayyaz Addrees contributed to this story.