President Donald Trump said Friday he will continue fighting with Turkey about its decision to detain Pastor Andrew Brunson, threatening additional action against the country.

“Turkey has been a problem for a long time,” Trump said to reporters as he left the White House. “They have not acted as a friend.”

The president called the charges against Brunson “phony,” adding that Brunson was not a spy.

“We haven’t seen the last of that. We are not going to take it sitting down,” Trump said. “They can’t take our people. So you will see what happens.”

On Thursday, Treasury Secretary Steven Mnuchin said the administration had plans to ratchet up sanctions on government officials if the country did not respond to demands for Brunson’s release.

“We’ve put sanctions on several of their Cabinet members,” Mnuchin said during a Cabinet meeting with Trump. “Working with you, we have more that we’re planning to do if they don’t release him quickly.”

Turkish President Tayyip Erdoğan called for a boycott of United States technology, such as the iPhone, in response to the additional sanctions and tariffs leveled by the Trump administration.

Trump also mentioned on Twitter Thursday the ongoing standoff with Turkey.

“Turkey has taken advantage of the United States for many years. They are now holding our wonderful Christian Pastor, who I must now ask to represent our Country as a great patriot hostage,” he wrote. “We will pay nothing for the release of an innocent man, but we are cutting back on Turkey!”: