Military trade ties between the United States and Russia have weakened after a deal to buy 15 Mi-17 helicopters from Russia’s state arms exporter Rosoboronexport (ROE) was scrapped after it was revealed that the company was still supplying arms to Syria.

“I applaud the [U.S.] Defense Department’s decision to cancel its plan to buy 15 additional Mi-17 helicopters from Rosoboronexport,” U.S. Sen. John Cornyn (R-Texas) said in a statement, the Associated Press (AP) reported. Cornyn has been leading a push to stop the Pentagon from making the purchase of the helicopters that were due for service in Afghanistan after it was revealed that Moscow was continuing to supply weapons to President Bashar Assad’s Syrian military.

According to a Department of Defense spokesperson, the additional helicopters had never been agreed upon and were “above and beyond” the 63 helicopters that had been ordered from ROE by the DoD in the past three years. The most recent purchase of 30 Mi-17 helicopters in June was while the civil war was raging in Syria, but Congress was unable to prevent the deal from going through.

Arms deals like the one made by the DoD don’t just include the aircraft but also deals on future parts, training and maintenance for a set period of time, so it’s unlikely that America’s relationship with the company will be severed.

The helicopters were supposed to be purchased and given to the Afghanistan security force, paid for by congressional funds. Those plans have now been shelved, but all previously agreed-upon purchases from ROE will be delivered.

This is not the first time the Department of Defense has done business with ROE. Records show that nine contracts amounting to more than $1 billion have been given to the controversial Russian company, which in 2008 supplied Iran with an S-300 anti-aircraft system after the learning that the U.S. had agreed to supply Israel with GBU-39s bombs.

The United States bought 21 Mi-17s in 2011 at a cost of $367.5 million and purchased an additional 30 in June 2013 for $553.7 million to serve in Afghanistan where the specialized helicopter is well suited to the hot and high environment.

Rosoboronexport representatives were not available for comment.