Flooding that has killed at least 20 people and forced some 340,000 from their homes in Indonesia's capital showed no sign of abating Sunday, as overflowing rivers swollen by days of rain again inundated the city.

The government dispatched medical teams on rubber rafts into the worst-hit districts amid fears that disease may spread among residents living in squalid conditions with limited access to clean drinking water.

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"Jakarta is now on the highest alert level," said Sihar Simanjuntak, another official monitoring the water levels of the many rivers that crisscross the city of 12 million people.

The death toll from flooding in Jakarta reached 20 as of Sunday afternoon, said Edi Darma, an official at Jakarta's Flooding Crisis Center.

Dr. Rustam Pakaya, from the health ministry's crisis center, said 339,138 people had been forced from their homes in Jakarta and its satellite towns.

Incessant rain over Jakarta and hills to its south from Thursday triggered the city's worst floods in recent memory, highlighting the country's infrastructure problems as it tries to attract badly needed foreign investment.

Waters reaching 4 meters (13 feet) high in places have inundated more than 20,000 homes, school and hospitals in poor and wealthy districts alike, forcing authorities to cut off electricity and water supplies and paralyzing transport networks.

Most of the homeless are staying with friends or family on higher ground at mosques and government agencies. Some are holding out on the second floors of their homes, refusing to be relocated by soldiers in rubber dinghies, officials said.

"We fear that diarrhea and dysentery may break out, as well as illnesses spread by rats," Dr. Pakaya said. "People must be careful not to drink dirty water."

In some districts, residents reported that waters receded slightly Sunday, but in others fresh flooding occurred as heavy rains over the southern hills in Puncak caused rivers to swell across the city.

Yusnizar, a 53-year-old living in housing estate on Jakarta's western outskirts, said some 1,000 houses were awash with one-meter high muddy water.

"Fortunately, people here are helping each other," said Yusnizar, who goes by a single name.

Indonesia's meteorological agency is forecasting rain for the next two weeks.

Environment Minister Racmat Witoelar blamed poor urban planning for the disaster.

"Authorities hand out (building permits) even though they clearly violate environmental impact studies," The Jakarta Post newspaper quoted him as saying.

Jakarta Governor Sutiyoso, who was criticized when massive floods struck the city five years ago, blamed widespread deforestation in Puncak, saying it had destroyed water catchment areas.

Seasonal downpours cause dozens of landslides and flash floods each year in Indonesia, a sprawling archipelago of 17,000 islands, where millions of people live in mountainous areas or near fertile plains.

Jakarta is regularly struck with floods, though not on the scale as in recent days. Dozens of slum areas near rivers are washed out each year. Residents either refuse or are too poor to vacate the districts.

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