At least 20 people were killed in northern India Sunday after a roof collapsed at a crematorium amid heavy rains, police said.

Rescue workers spent hours searching the rubble for survivors of the collapse, which occurred in the city of Ghaziabad on the outskirts of New Delhi.

Local media reported that 38 people were rescued, while at least 15 were injured and taken to hospital, according to the Press Trust of India.

"We have a confirmation of 20 bodies thus far but the number may rise," local police officer Mahipal Singh told AFP, adding that the cremation had been for an elderly individual who was not a Covid-19 victim.

"They took shelter under the newly constructed structure... The structure could not bear the rain and collapsed, leaving these persons dead."

Prime Minister Narendra Modi late Sunday tweeted his condolences to the victims' families.

Building collapses are frequent in India. Many firms use cheap materials and bribe officials to evade regulations, while on-site safety is lax.