Turkey and the United States remain on a collision course after President Donald Trump said he would not bargain with Ankara to win the release of a detained American pastor in a dispute that has pushed the countries’ strategic alliance to the brink and has roiled Turkey’s economy.

A war of words over Andrew Brunson, a 50-year-old evangelical church leader from North Carolina held by Turkey for nearly two years on terrorism charges, turned violent on Monday when gunmen opened fire on the US Embassy in Ankara. Turkish police arrested two men for carrying out the attack, in which no one was hurt.

Trump has imposed sanctions on two Turkish cabinet ministers he holds responsible for Brunson’s detention and tariffs on Turkish metal imports to pressure President Recep Tayyip Erdogan to free the pastor. Turkey's currency — already sagging as inflation soars and the corporate sector creaks under massive debt — has lost a quarter of its value this month amid fears harsher US measures may be in the pipeline.

Erdogan has accused the United States and other shadowy forces of attempting to undermine his government in an “economic war” and warned the United States it risks losing its NATO partner. The tough talk has won Erdogan support from ordinary Turks but has terrified investors, and last week two ratings agencies pushed Turkish debt deeper into non-investment-grade territory.