The group, led by Democratic Senator Bob Menendez, made the warning in a letter to the US State Department on Friday.
“We are writing today to specifically inquire about reported negotiations between Russia and certain countries over sales of the Russian government’s S-400 air defense system and whether these reported deals could trigger mandatory CAATSA sanctions,” the letter said, referring to the Countering America’s Adversaries Through Sanctions Act (CAATSA).
“Under any circumstance, a S-400 sale would be considered a ‘significant transaction’ and we expect that any sale would result in designations,” it added.
The S-400 is an advanced Russian missile system designed to detect, track, and destroy planes, drones, or missiles as far as 402 kilometers away.
The senators also called on the State Department to provide detailed analysis on the current status of Russian S-400 talks with China, Turkey, India, Saudi Arabia, Qatar, and any other country.
Menendez and the other signatories to the letter demanded information on how the State Department was planning to halt the Russian sales of S-400 to foreign nations and reiterated Washington’s accusations of Russia’s “aggression” in Ukraine.
The letter came a day after the Treasury Department used the CAATSA legislation along with an amended executive order to impose sanctions on five Russian entities and 19 individuals for their alleged meddling in the 2016 US presidential election and other “malicious cyber attacks.”
US President Donald Trump has repeatedly denied that Russia tried to influence the US election in his favor by allegedly damaging the presidential campaign of Democratic candidate Hillary Clinton.
The Thursday sanctions block all property of those targeted that is subject to US jurisdiction and prohibits American citizens from engaging in transactions with them.
Many of the main entities and individuals targeted already face travel bans and assets freezes put in place under the administration of former US President Barack Obama for alleged Russian interference in Ukraine.
Russia denies any involvement in the Ukrainian crisis, as well as the presidential election meddling accusations.