Pakistani officials on Sunday said a suicide bomber struck a public park in the eastern city of Lahore, leaving more than 50 people dead and 150 injured, with the death toll expected to rise.

"The toll has risen to 56. The rescue operation is continuing," said Lahore's top administration official Mohamed Usman.

"We have called for military help. Soldiers have reached the site and are helping with rescue and security," Usman added.

Pakistani deputy inspector general of police Haider Ashraf said the attack took place as Christians in the country celebrated the festival of Easter, although it was unclear whether members of the minority group were targeted.

The attack occurred near the park's playground, with women and children comprising the majority of casualties, local media reported citing health officials.

"We are in a state of war. We have beefed up security in Lahore. The terrorists wanted to target innocent people," Ashraf told DW.

Punjab Chief Minister Shehbaz Sharif "severely condemned the blast" that occurred in the parking lot of Lahore's Gulshan-i-Iqbal park.

"The chief minister expressed [a] deep sense of sorrow and grief over the loss of precious human lives," said a statement from the Punjab government published on its official Facebook page.

Tanvir Shahzad, DW's Lahore correspondent, said authorities reacted swiftly to the attacks.

"The government has announced three days of mourning and ordered the closure of all public parks in the eastern city of Lahore with immediate effect," said Shahzad.

ls/se (Reuters, dpa, AFP, AP)