Trump puts pressure on Turkey by doubling down on tariffs

President Donald Trump announced Friday that he is doubling tariffs on steel and aluminum from Turkey amid heightened tensions between the two nations.

Trump made his unexpected announcement on Twitter from his golf club in Bedminster, New Jersey, as the Turkish currency, the lira, fell to all-time lows against the U.S. dollar.

"I have just authorized a doubling of Tariffs on Steel and Aluminum with respect to Turkey as their currency, the Turkish Lira, slides rapidly downward against our very strong Dollar! Aluminum will now be 20% and Steel 50%," Trump said in a tweet.

Earlier this week U.S. and Turkish officials met in Washington to discuss issues that have pitted the two NATO allies against each other.

Despite Trump's insistence, Turkey has not budged in freeing American pastor Andrew Brunson, who has been detained by Turkey for almost two years on charges that he was working with a terrorist organization and was a spy. The Treasury Department announced fresh sanctions on two Turkish government officials in response to Turkey's refusal to let Brunson go.

The president is "not happy with Turkey's decision not to release Pastor [Brunson]," White House press secretary Sarah Sanders said.

In a statement, the White House said the president had authorized the preparation of documents to raise tariffs, citing national security concerns.

"Section 232 tariffs are imposed on imports from particular countries whose exports threaten to impair national security as defined in Section 232, independent of negotiations on trade or any other matter," White House deputy press secretary Lindsay Walters said in a statement.

But it's unclear exactly how Turkey is threatening national security. A Republican ally of the president, Sen. Lindsay Graham of South Carolina, said Trump's decision was retaliation against Turkey for not releasing Brunson. Graham called Turkey's case against Brunson a "sham."

"It's very unfortunate that the Trump administration had to retaliate against Turkey for their continued refusal to release Pastor Brunson and other Americans being held in Turkish custody," Graham said.

In what appeared to be a diplomatic slight, Turkey announced soon after Trump's tweet that Erdogan had held a phone call with Russian President Vladimir Putin about "strengthening economic and trade ties."

ABC News' Engin Bas and Anastasia Bagaeva contributed to this report.