In an effort to keep Syria from restarting its production of deadly nerve agents, Israel has carried out at least two attacks on chemical weapons sites in the war-torn country in the past two years, The Washington Post reported on Monday. 

Citing current and former US and Western intelligence officials, the newspaper describes alleged Israeli airstrikes on June 8 that targeted three military sites linked to Syria’s former chemical weapons program. The strikes in Damascus and Homs reportedly killed seven Syrian soldiers, including an engineer who worked at a secret military lab.

Israel has carried out hundreds of strikes on Iran-linked forces in Syria since the war began in 2011 but rarely acknowledges the attacks. Israeli officials declined to confirm to the Washington Post whether its raids targeted Syria’s chemical weapons production.

The Post reports that in both the June raid and a similar one the year before, Israel had intelligence indicating Syria was “acquiring chemical precursors.” It’s unclear whether the attacks, which Israel intended to be “preemptive,” managed to degrade or destroy Syria’s production capabilities, the newspaper’s sources said.