The United States reportedly carried out a secret cyber operation against Iran in the wake of the Sept. 14 attacks on Saudi Arabia’s oil facilities.

Citing U.S. officials, Reuters reports that the operation affected physical hardware and took place in late September and took aim at Tehran’s ability to spread “propaganda.”

The United States, Saudi Arabia, Britain, France and Germany have publicly blamed the Sept. 14 attack on Iran, which denied involvement in the strike. The Iran-aligned Houthi militant group in Yemen claimed responsibility.

The Pentagon declined to comment about the cyber strike.

Iran has used such tactics against the United States. This month, a hacking group that appears linked to the Iranian government tried to infiltrate email accounts related Trump’s re-election campaign.

Over 30 days in August and September, the group, which Microsoft dubbed “Phosphorous,” made more than 2,700 attempts to identify consumer accounts, then attacked 241 of them.