Sixty-six US senators signed a letter released on Friday urging Turkey's President Recep Tayyip Erdogan to release an American pastor on trial in Turkey on charges he was linked to a group accused of orchestrating a failed military coup.
Andrew Brunson, a Christian pastor who has lived in Turkey for more than two decades, was indicted on charges of helping the group that Ankara holds responsible for a failed 2016 coup against President Erdogan. He faces up to 35 years in prison.
The letter, led by Republican Senator Thom Tillis, who represents Brunson's home state of North Carolina, and Democrat Jeanne Shaheen, said the Senate backs efforts to strengthen cooperation between US and Turkish law enforcement.
"However, we are deeply disturbed that the Turkish government has gone beyond legitimate action against the coup plotters to undermine Turkeys own rule of law and democratic traditions," it said.
Shaheen and Republican Senator James Lankford, who are members of the Senate Appropriations Committee, said in a separate statement that they would push for sanctions against Turkish officials in an upcoming spending bill in response to Brunson's imprisonment.
US President Donald Trump also voiced his support for Brunson on Twitter this week, writing, "They call him a spy, but I am more a spy than he is."
In their letter, the senators warned that unspecified measures might be necessary to ensure the Turkish government "respects the rights of law-abiding citizens" of the United States to be in Turkey without fear of prosecution.
Brunson's trial is one of several legal cases roiling US-Turkish relations. The two countries are also at odds over US support for a Kurdish militia in northern Syria that Turkey considers a terrorist organisation.
Last year, Erdogan suggested that Turkey may release Brunson if the US hands over Fethullah Gulen, a Muslim cleric living in Pennsylvania whom Ankara has blamed for the failed military coup.
The letter was signed by 43 Republicans and 23 Democrats.