An ammonia leak in Eastern Ukraine has contaminated an area with a radius of about 2.5 kilometers, officials informed on Monday. Even though Sumy regional governor Dmytro Zhyvytskyy did not specify what caused the leak, state media reports suggest that a Russian airstrike caused the leak.

Emergency services have been deployed to the site and are currently working to minimise the spread.

Also Read: Amid new bombings, Ukraine now seen as a war of attrition

The ammonia leak was reported at the Sumykhimprom plant, which is on the eastern outskirts of Sumy, which has a population of about 263,000 and has been regularly shelled by Russian troops in recent weeks.

Zhyvytskyy said that the nearby village of Novoselytsya, about 1.5 kilometers southeast of Sumy, is under threat. “For the center of Sumy, there is no threat now, since the wind does not blow on the city”, the governor added, according to reports from Associated Press.

Even though the extent of the leak has not been cleared up so far by authorities, residents of the area were advised to protect themselves from ammonia exposure and seek shelter in in basements or on lower levels of buildings.

“Ammonia is lighter than air, therefore shelters, basements and lower floors should be used for protection”, Sumy governor Zhyvytskyy wrote in a social media post, according to reports from AFP.

Also Read: Russian troops were ‘shooting civilians’, say Ukrainian refugees in Poland

According to the New York Health Department, exposure to ammonia by inhalation can cause ” immediate burning of the nose, throat and respiratory tract.” Higher concentrations of ammonia– when in contact with the skin– may cause severe injury and burns.

Russian forces, while invading Ukraine, took control of the Chernobyl nuclear plant — site of the world’s worst nuclear accident in 1986– after briefly damaging it with shelling.