More than 50 people were killed when a suicide bomber blew himself up on Sunday evening near the main gate of the crowded and popular Gulshan - e - Iqbal park here, officials said.
Superintendent of Police Muhammad Iqbal of Iqbal Town area, where the park is located, confirmed it was a suicide attack and said 53 people had been killed.
More than 200 people were injured in the ghastly tragedy. Many of them were in critical condition in three main hospitals which frantically appealed to Lahore residents to donate blood.
The deafening explosion took place around 6. 30 p. m. when the park was teeming with families, especially women and children, enjoying the Sunday and Easter holiday.
Police officials said the blast occurred only a few metres from the children's swings.
Media reports quoted witnesses as saying that body parts were strewn everywhere.
Daily Pakistan said the park was packed when the attack took place. "There were body parts everywhere, " the Dawn quoted a witness as saying.
Deputy Inspector General of Police Mohammad Usman also confirmed that it was a suicide attack and said that ball bearings used in the explosive had been found at the parking lot.
Police rescuers and over 20 ambulances ambulances raced to the park, which is crowded every weekend, and ferried the injured to hospitals.
Others who survived the explosion helped to take the injured to hospitals in taxis and and rickshaws.
Deputy Inspector General of Police Haider Ashraf said the suicide bomber blew up in the parking lot. Xinhua news agency said that the terrorist's body parts were found at the site.
The first international reaction came from India, where Prime Minister Narendra Modi denounced the deadly blast.
"I strongly condemn it. My condolences to families of the deceased and prayers with the injured: PM, " Modi tweeted.
In Pakistan, shocked leaders condemned the brutal terror. They included President Mamnoon Hussain, Prime Minister Nawaz Sharif and Chief Minister Shahbaz Sharif of Punjab.
ARY News said 5 - 6 kg of explosives may have been used in the explosion, which was heard in a large part of Lahore, capital of Punjab province.
An emergency was declared in all government hospitals in Lahore. While police cordoned off the park, troops were also rushed to the site to help the civilian authorities.