The United States is planning to impose further sanctions on Iran as it ratchets up the pressure to attempt to force the Islamic Republic from its proxy, Syria.

Short of a full-blown military plan, the strategy would stress political and diplomatic efforts to oust Iran out of Syria by weakening it economically. It would pause reconstruction assistance from areas where Iranian and Russian forces are present, three people familiar with the plan told the media outlet. An example of such an area is Aleppo, a rebel stronghold until the Syrian regime won it back in 2016.

Additionally, the United States would impose sanctions on Russian and Iranian firms working on reconstruction in Syria.

“There’s a real opportunity for the U.S. and its allies to make the Iranian regime pay for its continued occupation of Syria,” Foundation for Defense of Democracies Mark Dubowitz told NBC News.

[wpipa id=”94167″]

The United States is not allowed to specifically expand the U.S. military mission in Syria to directly target Iranian assets, according to legal experts, because that would put it on the wrong side of the Authorization for Use of Military Force passed by Congress in 2001. However, the U.S. army is allowed to strike the Iranian military in self-defense under that same authorization.

“The United States will continue to seek to hold [Syrian President Bashar al-] Assad accountable for his crimes,” an administration official told NBC News. “Pursuant to the National Defense Authorization Act for Fiscal Year 2018, the administration will soon submit to Congress a strategy for Syria that reflects the president’s key priorities.”

This development follows the U.S. sanctioning of 22 businesses on Tuesday for providing financial support to Iran’s Revolutionary Guard’s militia, which recruits, trains and deploys child soldiers to fight in Syria and other places. Iran responded negatively on Wednesday to the announcement.

“America’s new sanctions are a clear insult to international and legal mechanisms and a result of the American government’s blind vindictiveness against the Iranian nation,” declared foreign ministry spokesman Bahram Ghasemi.