Several members of the United States Congress, on both sides of the aisle, have been quietly blocking U.S. arms sales to Turkey for the past two years.

This bipartisan move has been in response to Turkey’s decision to buy Russian made S-400 antiaircraft missiles and to Turkey’s increasingly close relationship to Russia and President Vladimir Putin. The story was first broken by Defense News and has since been confirmed by other news sources. 

Turkey is a longtime member of NATO and has been a close ally of the U.S. for decades. However, its relationship with the U.S. has become increasingly strained. Erdogan has been turning Turkey into a less secular state. He has converted the Hagia Sophia into a mosque and openly called for Turkey to become a new caliphate. Turkey also invaded Syria and attacked Kurdish-held areas, something which angered Congress. This latest revelation won’t help ease matters between the two countries. 

The purchase of the Russian S-400 system, caused Turkey to be ousted from the F-35 joint strike fighter program. Additionally, there are at least two significant arms deals which are on hold for the foreseeable future: The two countries have a follow-on contract for F-16 structural upgrades as well as export licenses for U.S.-made engines for attack helicopters that the Turks are selling for $1.5 billion to Pakistan.