LA PAZ, Dec. 15 (Xinhua) -- Bolivian authorities confirmed at least 20 deaths and more than 20 others missing following intense rainfall and river overflows that have struck communities in the department of Santa Cruz, the government said Monday.

Deputy Minister of Civil Defense Alfredo Troche reported seven fatalities as of Sunday. Additional bodies were found after rescue operations expanded and floodwaters receded.

"Unfortunately, we now have 20 confirmed deaths and more than two dozen missing," he said, adding that Santa Cruz has been declared a departmental disaster zone.

Heavy rains since Friday night caused the Pirai River and other tributaries to overflow, affecting at least 22 communities, mainly in the municipality of El Torno, one of the hardest-hit areas.

"As days pass and the weather improves, the number will likely increase because water levels are receding and rescue teams are working to find bodies that were unable to escape this force of nature," Troche said.

According to official information, entire neighborhoods were flooded and dozens of families had to be urgently evacuated.

Troche said about 600 families were affected in El Torno, while another 1,500 families were impacted in the Colpa Belgica area of Santa Cruz, where a bridge connecting the municipality to the road to Warnes collapsed.

With more rain forecast, the government announced preventive relocations for at-risk communities and is working toward declaring a national emergency. ■