Lebanon’s President Joseph Aoun on Wednesday accused Israel of committing an environmental crime after Israeli forces sprayed a “toxic substance” over southern Lebanese towns.

“This is an environmental and health crime against Lebanese citizens and their land,” Aoun was quoted as saying by Lebanon’s National News Agency.

On Monday, the United Nations Interim Force in Lebanon (Unifil) said it received notice from the Israeli army of planned aerial activity near the Blue Line and was asked to remain inside shelters

Unifil said it was informed by the Israeli military that it would spray a “non-toxic chemical substance” from the air over areas near the border.

Geneva-based Euro-Med Human Rights Monitor said that it had documented Israeli aircraft spraying chemical substances over extensive agricultural areas, particularly in the town of Ayta ash-Shaab and its vicinity in southern Lebanon.