CHANGSHA, July 20 (Xinhua) -- Four construction workers were trapped during underground operations at a road worksite in Changsha, capital of central China's Hunan Province, following heavy rainfall on Sunday afternoon, local authorities said.

The incident occurred at around 4:50 p.m. Sunday in the Heishipu area of the city's Tianxin District. As of 10:00 p.m. Sunday, two have been rescued and transported to hospital for treatment, according to the district's publicity department.

Search and rescue efforts for the remaining two workers are ongoing. ■