Islamabad, Feb 12 (IANS) Three people were killed and 10 others injured when the dome of an under-construction mosque collapsed in Lahore, local media reported.About 25 labourers were working at the mosque when the dome collapsed on Thursday, Xinhua news agency.The injured people were shifted to a nearby hospital where two of them were in critical condition.Police has launched investigation into the incident.According to preliminary reports, substandard construction material was the reason of the collapse. --IANS ksk/