Turkish media reported that sixteen people went on trial in Istanbul on Tuesday over charges of "political and military" espionage on behalf of Israel.
The defendants, including Palestinians and Syrians, were arrested in October in an operation by Turkey's national intelligence agency, MIT, according to the pro-government Sabah newspaper and other Turkish media.
Sabah said the initial hearings in the trial would last four days, with each of the defendants facing up to 20 years in prison if convicted.
The suspects allegedly spied on Palestinian and Turkish students and other people on behalf of Israel, operating in five separate groups, Sabah newspaper reported. Some of the suspects allegedly met with Israeli officials in Switzerland, Croatia, Romania and Kenya.
Turkish intelligence officers reportedly monitored the group for a year before they were arrested.
The trial comes less than two weeks after Turkish President Recep Tayyip Erdogan announced that he would be hosting President Isaac Herzog for an official visit to Turkey as early as late February — the first such visit by an Israeli leader in years.
Earlier Tuesday, Turkish Foreign Minister Mevlut Cavusoglu gave another nod to kickstarting ties with Jerusalem, saying such a move could help promote a two-state solution to the Israeli-Palestinian conflict, but reserved that it would not diminish Ankara's support for the Palestinian cause.