WASHINGTON • President Donald Trump has abruptly announced that the US would impose "large sanctions" on Turkey for detaining an American pastor accused of aiding a failed coup attempt there in 2016, escalating a bitter dispute between the two Nato allies.

Mr Trump's declaration on Twitter on Thursday appeared to be more of a muscular threat than an official statement of policy. The United States administration made no announcement of specific punitive measures against the Turkish government, and the White House declined to provide any details about the steps it was ready to take.

It came one day after Mr Andrew Brunson, 50, an evangelical pastor who has been imprisoned in Turkey for 21 months, was moved from jail to house arrest because of health concerns.

Mr Brunson is one of 20 Americans charged after the failed coup against President Recep Tayyip Erdogan. His case has elevated tensions between the US and Turkey even as Mr Trump has sought warmer relations with Mr Erdogan.

On Thursday, Mr Trump told Mr Erdogan in a private phone call that the pastor's continued imprisonment was unacceptable, according to a White House official who described the conversation on the condition of anonymity because he was not authorised to discuss it publicly.

And the US leader vowed on Twitter to impose substantial sanctions on Turkey for Mr Brunson's detention.

It would be an extraordinary step to impose sanctions on a Nato ally, and the Turkish government responded defiantly.

"No one dictates Turkey," Mr Mevlut Cavusoglu, Turkey's Foreign Minister, wrote in a tweet. "We will never tolerate threats from anybody. Rule of law is for everyone; no exception."

NYTIMES