Ethiopian Army soldiers prepare 18 August to bring help to residents.(AFP/File/Abraham Fisseha)

ADDIS ABABA (AFP) – Ethiopia stepped up evacuation warnings in low-lying areas as heavy rains threatened more of the flash floods that have already killed more than 600 people and affected tens of thousands around the country.

Authorities said unusually heavy seasonal downpours in the highlands had raised water levels to a critical level at three dams in the west, south and north and advised nearby residents to leave.

“The Ethiopian Meteorological Agency is asking people who live around the dams to move to higher ground to take precautionary measures, as the rain in the highlands is increasing and dams have water beyond their capacity,” it said Monday.

In a statement read on state radio and television, the agency urged civilians to tune in to the state channels for updates on the situation at dams on the Omo, Awash and Blue Nile rivers.

A similar warning was issued on Sunday by a government task force that said the rains might force the controlled release of water from the dams, worsening already devastating flood damage.

The threatened facilities are the Gilgel Gibe dam on the Omo, which has already flooded huge areas in the southwest, the Koka on the Awash River that has flooded in the east, and the Tise Aby on the Blue Nile in the north.

In addition to at least 626 people confirmed dead after floods across the country, some 250 villagers are still missing and around 73,000 are affected, many of them left homeless by the raging waters that have killed thousands of valuable livestock and flooded huge tracts of farmland.

Federal authorities and humanitarian groups are scrambling to deliver supplies to affected people, but driving rains and ruined infrastructure have obstructed efforts to aid the country’s flooded areas.

With poor weather continuing to hamper relief efforts, particularly in the southwest Omo River valley where 364 drowned last week and up to 8,000 remain marooned in 14 inundated villages, officials fear a rise in the death toll.

Already overwhelmed authorities have appealed for international aid, and US troops began relief work over the weekend in the town of Dire Dawa, about 500 kilometers (300 miles) east of Addis Ababa, hit by floods on August 6.

The 35 Djibouti-based US naval engineers set up dozens of tents to house many of the some 6,000 people displaced by the waters, which killed 256, and were erecting sanitation facilities amid growing fears of the spread of malaria and water-borne diseases.

Local authorities, who have banned hasty reconstruction across the township, are surveying the area before erecting buildings.

Meteorologists have warned that six areas in the north, west and south of the country will likely face further flood threats from the downpours that are expected to continue until the end of the wet season in September.

Ethiopia, home to some 70 million people, has suffered heavy floods and droughts in recent years, ruining agriculture that provides livelihood for the majority in the Horn of Africa nation.

In the past few years, flooding has affected large areas of eastern and southern Ethiopia, displacing tens of thousands of people and causing damage running into millions of dollars.

Last year at least 200 people were killed and more than 260,000 displaced when heavy rains pounded the region.

Humanitarian workers said low-lying parts of western Somalia, a lawless African nation to the southeast of Ethiopia, had been affected by floodwaters originating from the Ethiopian highlands, but the extent of damage remained unclear.