Two buses plunged into a flooded river after an old bridge collapsed in western India, leaving at least 22 people missing and feared dead, an official said Wednesday.

Rescuers had not found the buses or any survivors hours after the single-lane bridge on the Mumbai-Goa highway collapsed about midnight Tuesday, said Devendra Fadnavis, Maharashtra state's chief minister.

The two Maharashtra state-run buses were carrying a total of 18 passengers, two drivers and two conductors, according to Fadanavis.

He said the bridge, constructed in the 1940s, likely collapsed because it was buffeted by strong currents from the Savitri River, which was flooded by monsoon rains.

O.P. Singh, chief of the National Disaster Response Force, said that 80 rescuers, including divers, rushed to the area, but that their efforts were being hampered by heavy rains.

A helicopter hovered over the area trying to spot the buses or any bodies floating in the swollen river.

Various parts of India have been lashed by heavy downpours lately. The monsoon season runs from June to September.