India, April 1 -- Four people were killed and nine others sustained injuries following an explosion at a highway tunnel under construction in southwest China's Chongqing Municipality, local officials said on Tuesday.

The blast occurred on Monday afternoon at a construction site for a section of the national highway connecting Hubei and Sichuan provinces, according to the Wanzhou District transport commission.

Initial reports indicated that one person was missing and 12 others were wounded. By midnight on Tuesday, rescuers recovered the body of the missing individual. Three of the injured later succumbed to their injuries despite receiving medical treatment, the state-run Xinhua news agency reported.

Preliminary findings suggest the exp...