An explosion in the Pakistani city of Lahore has killed at least 38 people and injured dozens more, officials say.

The blast was in a large park in the south-west of the city, where many people had gathered late on Sunday.

Police told the BBC it appeared to be a suicide bomb. No group has said it was behind the blast.

There is speculation that Christian families out for the Easter weekend may have been the target.

All the major hospitals in the area have been put on an emergency footing to deal with casualties, local media report.

The explosion appears to have been at the main gate to the Gulshan-e-Iqbal park in an area where cars are usually left.

Lahore is the capital of Punjab, Pakistan's largest and wealthiest province and the political powerbase of Prime Minister Nawaz Sharif.

Pakistan has suffered regular incidents of Taliban-related violence, sectarian strife and criminal gang activity.

BBC/RI