Mike Pompeo (File Photo)

CIA Director Mike Pompeo says he sent a letter to a top Iranian military official warning him the United States would hold Tehran accountable for any attacks on American interests in Iraq by forces under Iranian control.

Pompeo said Iran is trying to strengthen its influence throughout the Middle East.

He said Saturday the letter he sent to Gen. Qassem Soleimani (kah-SEM' soh-lay-MAH'-nee) was never opened, but he wanted to send it because the general had indicated forces under his control might threaten U.S. interests in Iraq.

Pompeo, a staunch opponent of the Iran nuclear deal, also said Tehran currently is in compliance with the pact that provided Iran relief from sanctions in exchange for reining in its nuclear program.

He spoke at a defense forum in Simi Valley, California.