LONDON — Turkey said on Thursday that it will send an American citizen suspected of being an Islamic State group fighter back to the U.S. after he spent four days stranded on a small stretch of land between Greece and Turkey.

The man was initially deported to Greece on Monday, Turkey's Interior Ministry announced, but was stuck in the "buffer zone" near the border town of Kastanies after Greece refused to accept him.

"Necessary actions are being taken for the deportation process after the committal from U.S. for accepting the person and issuing travel documents," according to a Turkish statement.

NBC News has not independently verified the man's identity or nationality.

U.S. officials did not immediately respond to the announcement, but on Monday a State Department spokesman said: "We are aware of reports of the detainment of a U.S. citizen by Turkish authorities. Due to privacy considerations, we have no further comment."

Turkish officials say eight other suspected ISIS fighters would be sent home to European nations Thursday, including one to the U.K and seven to Germany.

This week Turkey began a long-promised operation to send captured foreign ISIS militants to their home nations. One American fighter has already been sent to the U.S., it said.

Interior Minister Suleyman Soylu said last week that Turkey was not a "hotel" for militants, adding that there are around 1,200 of them in Turkish jails.

The situation is complicated by several Western states having stripped known ISIS fighters and collaborators of their citizenship, essentially leaving them stateless.