Olympic officials have postponed the men's triathlon competition Tuesday because of unsafe water conditions in the Seine river.

Levels of E. coli remain too high for athletes to swim in the water as of Monday, according to NBC News.

“Despite the improvement on the water quality levels in the last hours, the readings at some points of the swim course are above acceptable levels,” said World Triathlon, the international governing body for swimming at the Olympics said in a statement.

The competition has tentatively been rescheduled for Wednesday but officials said it might be further delayed until Friday.