WASHINGTON, Aug. 15 (Xinhua) -- U.S. Vice President Mike Pence on Wednesday warned Turkey not to test the resolve of U.S. President Donald Trump on the case of the detained American pastor Andrew Brunson.

Pence tweeted that "Turkey would do well not to test" Trump's resolve "to see Americans who are wrongfully imprisoned in foreign lands returned home to the United States."

Saying that Brunson is innocent and "justice demands that he be released," Pence noted that he and Trump "continue to stand firm" until Brunson is released and returns to the United States.

Also on the same day, White House spokesperson Sarah Sanders said that "Turkey and specifically President Erdogan have treated pastor Brunson... very unfairly, very badly."

The U.S. Department of the Treasury on Aug. 1 slapped sanctions on Turkey's justice and interior ministers, citing their roles in the detention of the U.S. pastor.

Brunson, a 50-year-old Christian pastor, was detained two years ago in Turkey on spying charges, and faces up to 35 years in prison if found guilty.

He was indicted on charges of having links with the outlawed Kurdistan Workers' Party and the Fethullahist Terrorist Organization, which Turkey accuses of being behind a coup attempt in 2016 to topple Turkish President Recep Tayyip Erdogan.

Pence had warned before the sanctions that the United States would slap significant sanctions on Turkey unless it releases Brunson "immediately."