At least 67 people were killed and over 300 others injured in a deadly suicide explosion near the crowded and popular Gulshan - e - Iqbal park here on Sunday, rescue and security officials said.
"Some 65 - 70 people have been killed, included women and children, and over 250 were injured, " an Edhi spokesperson told IANS.
Superintendent of Police Muhammad Iqbal of Iqbal Town area, where the park is located, confirmed it was a suicide attack.
Many of the injured were in critical condition in various 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.
Pakistan Army troops have been deployed as the park and surrounding area has been cordoned off by the security forces.
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.