At least 11 worshippers were killed when the roof of a mosque collapsed in the eastern Pakistani city of Lahore Tuesday, officials said, adding the death toll may rise.

At least 11 worshippers were killed when the roof of a mosque collapsed in the eastern Pakistani city of Lahore Tuesday, officials said, adding the death toll may rise.

The incident took place in Daroghawala, a low-income neighbourhood in the outer city with narrow and congested streets.

"The bodies of at least 11 worshippers have been pulled out from the rubble of the roof, while an unknown number of people are still buried," rescue official Jam Sajjad told AFP.

There were up to 30 people at the daily afternoon prayer.

"We fear that the death toll might rise. The roads there are very crowded, preventing heavy machines from entering the area to remove the debris. The people of the area are also helping the rescue effort," Sajjad said.

Local government official Usman Ahmed confirmed the roof collapse and toll.

Safety standards, particularly in construction, are very lax in nuclear-armed but impoverished Pakistan.

At least 21 people including including 16 women and four children died when a factory collapsed in Lahore in 2012.

The collapse of the Margalla Towers apartment block in Islamabad in a 2005 earthquake killed 78 people, with shoddy construction blamed.