ISTANBUL: The Turkish lira firmed against the dollar on Thursday, a day ahead of a hearing in the Turkish trial of a U.S. pastor which has strained relations between the two countries, with one U.S. media report saying a deal had been reached on his release.

The lira strengthened as far as 5.9025 against the dollar after the report from a close of 6.0767 on Wednesday. It stood at 5.9190 at 1910 GMT.

The trial of Andrew Brunson, an evangelical Christian pastor from North Carolina, is among various sources of tension between the NATO allies and has been one of the factors in a 40 percent slide in the lira's value this year. He is facing terrorism charges, which he denies.

NBC News reported that the White House expected Brunson to be released by Turkey and returned to the United States in the coming days, according to two senior administration officials and another person briefed on the matter.

NBC cited its sources as saying that under an agreement which U.S. administration officials recently reached with Turkey, Brunson is supposed to be released after certain charges against him are dropped at his next court hearing on Friday.

The report could not immediately be confirmed.

Brunson's lawyer told Reuters earlier that new prosecution witnesses expected to testify on Friday in his trial lacked relevance as their testimony will focus on incidents after his arrest.