Thailand's Prime Minister Yingluck Shinawatra is warning the capital of Bangkok to brace for floods after ordering officials to open floodgates that have so far kept the water away.

Ms. Yingluck said Thursday that engineers cannot stop the water forever and has ordered the gates open to try to drain the waters that have already flooded Bangkok's northern suburbs.

But she said there is a chance that the canals running through the city to the Gulf of Thailand will overflow into the streets of the capital.

Many in the city are rushing to stock up on food and drinking water while those in the flooded north have already fled their homes.

Months of heavy monsoon rains have soaked large parts of Southeast Asia, killing 320 people in Thailand. Millions have been forced from their homes. Hundreds have also died in Cambodia, Laos, and Vietnam.