A pair of top White House officials is pushing to broaden the war in Syria, viewing it as an opportunity to confront Iran and its proxy forces on the ground there, according to two sources familiar with the debate inside the Donald Trump administration.

Ezra Cohen-Watnick, the senior director for intelligence on the National Security Council, and Derek Harvey, the NSC’s top Middle East advisor, want the United States to start going on the offensive in southern Syria, where, in recent weeks, the U.S. military has taken a handful of defensive actions against Iranian-backed forces fighting in support of Syrian President Bashar Assad.

Their plans are making even traditional Iran hawks nervous, including Defense Secretary James Mattis, who has personally shot down their proposals more than once, the two sources said.

The situation in southern Syria has escalated in recent weeks, after a U.S. warplane shot down an Iranian-made drone that had attacked U.S. forces on patrol with Syrian allies near an American outpost at al-Tanf. The drone attack came after two U.S. airstrikes on Iranian-backed Shiite militias, which had moved too close to the Americans’ garrison.