Schools and roads were closed as flash floods from Tropical Storm Nongfah swept through northern Thailand.

Homes, shops and farmland were left underwater as the Pa Sak River burst its banks in Phetchabun province on Sunday.

Residents scrambled to build sandbag walls while soldiers helped locals evacuate from flooded houses.

Highways were submerged, with a fallen traffic sign causing traffic congestion as it blocked cars on Highway 2016.

Mayor Kitti Phuachuay said water pumps have been deployed to help lower water levels.

The Thai Meteorological Department on Sunday said that Tropical Storm Nongfah had weakened into a strong low-pressure system moving into northern Thailand.

Combined with an intensifying southwest monsoon, the weather system is expected to bring heavy to very heavy rainfall across 43 provinces over the next one to two days.

Authorities warned residents to constantly monitor weather updates.