One labourer was killed and 45 others injured when an under-construction building inside the Indian Air Force base in Jamnagar district of Gujarat collapsed on Thursday, district officials said.

Rescue teams evacuated at least 46 people from the debris and searches are on for more people feared trapped, Jamnagar district Resident Deputy Collector Ketan Thakker told PTI.

One of the rescued labourers later succumbed to his injuries at the Guru Govind Singh hospital in Jamnagar, he said.

The official said that condition of two persons among those rescued from the debris was critical and they were receiving treatment at the hospital.

However, one of the critically injured will be taken to Ahmedabad for advanced medical care.

"As of now the focus of the administration is to rescue those still trapped beneath the debris. The rescue teams of Jamnagar and Rajkot fire brigade are engaged in work of removal of debris," officials said.

More people are likely to be trapped under the debris, Thakker added.

The officials, however, did not ascertain the reason of the collapse.