Russia warns that the dam’s destruction poses a risk to Crimea’s water supply.

The destruction of the Kakhovka dam could potentially spell trouble for a canal that supplies water to Crimea, which has been a point of geopolitical tension between Kiev and Moscow for years, Russian officials warned on Tuesday.

The channel, the Northern Crimean Canal, runs about 400 kilometers from the reservoir above the dam to Crimea, the Black Sea peninsula that Russia illegally annexed in 2014.

For many years it served as Crimea’s main source of water, but soon after annexation, Ukraine blocked the water flow. Russia restored it after invading and occupying the area around the canal last year.

Kremlin spokesman Dmitri S. Peskov said in a briefing Tuesday that the water level in the reservoir fell due to the destruction of the dam, reducing the supply to the canal. Only a small part of the canal’s water supply is used for drinking water. Most of it is used for agricultural purposes in Crimea.

Sergei Aksyonov, the Kremlin-installed leader of Crimea, said on Tuesday there was a risk that the water in the canal would become shallow.

Mr. Aksyonov wrote in the Telegram messaging app that 40 million cubic meters of water remained in the canal and work was underway to minimize losses. He said that Crimea’s reservoirs were 80 percent full, adding that there was enough drinking water for the inhabitants of the peninsula.

“In the coming days, the situation will become clear, as will the potential risks,” Mr Aksyonov wrote.