Turkish Deputy Foreign Minister Sedat Onal (L) is greeted by a U.S. State Department protocol official as ambassador to the U.S. Serdar Kilic looks on upon their arrival at State Department in Washington, U.S., August 8, 2018. REUTERS/Yuri Gripas

ANKARA (Reuters) - Turkey’s newly appointed deputy foreign minister, Sedat Onal, will head a delegation that will go to the United States to discuss tensions between the NATO allies, a source in the Turkish foreign ministry said on Tuesday.

Relations between the two countries have steadily worsened, strained by differences on Syria policy and over the trial of U.S. pastor Andrew Brunson in Turkey. A widening trade spat sent the lira currency to a record low on Monday.

Broadcaster CNN Turk had earlier reported that Turkey and the United States had reached pre-arrangements on certain issues and the delegation would go to Washington in two days to discuss the row.

“Our deputy foreign minister Sedat Onal will head the delegation,” the source said, without elaborating. The source spoken on the condition of anonymity.

U.S. President Donald Trump’s administration has demanded that Turkey release Brunson, an evangelical pastor who has lived in Turkey for more than two decades and has been charged with supporting a group that Ankara has blamed for an attempted coup in 2016. Brunson has denied the accusations.

Last week, Washington imposed sanctions on President Tayyip Erdogan’s justice minister and interior minister, saying they played leading roles in organizations responsible for Brunson’s arrest. Erdogan has said Turkey would retaliate against the sanctions.

Over the weekend, the U.S. Trade Representative (USTR) said it was reviewing Turkey’s duty-free access to the U.S. market, after Ankara imposed retaliatory tariffs on U.S. goods in response to American tariffs on steel and aluminum. The move could affect $1.7 billion of Turkish exports.

The U.S. Embassy in Ankara said on Tuesday that the United States continued to be a solid ally of Turkey despite ongoing tensions, adding that the two countries had an active economic relationship.