On Thursday, a bipartisan group of US congressmen filed legislation to prohibit the US government from recognizing Bashar al-Assad as Syria’s president and to strengthen Washington’s power to apply sanctions as a message to other countries repairing relations with Assad.

The measure, originally reported by Reuters, would bar the United States from recognizing or restoring ties with any government in Syria led by Assad, who is subject to U.S. sanctions, and builds on the Caesar Act, a U.S. statute that put further sanctions on Syria in 2020.

The bill comes after Arab states turned the page on years of confrontation with Assad on Sunday by letting Syria back into the Arab League, a milestone in his regional rehabilitation even as the West continues to shun him after years of civil war.

Regional countries, including Saudi Arabia, Qatar and others, had for years supported anti-Assad rebels, but Syria’s army – backed by Iran, Russia and allied paramilitary groups – regained most of the country. The icy ties with Assad began to thaw more quickly after devastating earthquakes in Syria and Turkey in February.

The United States has said it will not normalize ties with Assad, and its sanctions remain in full effect.

“Countries choosing to normalize with (the) unrepentant mass murderer and drug trafficker, Bashar al-Assad, are headed down the wrong path,” U.S. Representative Joe Wilson, the chair of the Subcommittee on the Middle East, North Africa, and Central Asia, said in a statement.

The bill was introduced by Wilson alongside House of Representatives Foreign Affairs Committee Chairman Michael McCaul and co-chairs of the Free, Democratic and Stable Syria Caucus, Republican French Hill and Democrat Brendan Boyle; among others.

The legislation is a warning to Turkey and Arab countries that if they engage with Assad’s government, they could face severe consequences, a senior congressional staffer who worked on the bill told Reuters.

“The readmission of Syria to the Arab League really infuriated members and made clear the need to quickly act to send a signal,” the staffer said.

The bill’s provisions include a requirement for an annual strategy from the secretary of state for five years on countering normalization with Assad’s government, including a list of diplomatic meetings held between Syria’s government and Turkey, the United Arab Emirates, Egypt and others.

The bill would also clarify the applicability of U.S. sanctions on Syrian Arab Airlines and another carrier, Cham Wings. Under the proposed bill, countries that allow the airlines to land would face sanctions against that airport, the staffer said.

If passed, the bill would also require a review of transactions, including donations over $50,000 in areas of Syria held by Assad’s government by anyone in Turkey, the UAE, Egypt and several other countries.