Bucharest prosecutor Viviana Ciuca told The Associated Press that Kamil Demirkaya was detained based on an extradition request from Turkey for "being a member of criminal, terrorist group."
The Zaman Romania newspaper said their employee was arrested "on the order" of Turkish President Recep Tayyip Erdogan. Demirkaya later appeared in court and is free pending a court ruling.
The case is delicate for Romania, which takes over the EU's rotating presidency on. Jan. 1.
Demirkaya denied allegations of terrorism, saying he had been a teacher in Turkey and abroad for 11 years and had worked as a journalist for eight years.
"I don't recall ever killing a fly or an ant," he told Digi24 news channel. "Unfortunately, I am accused of terrorism." He said Romanian authorities had followed legal procedures following Turkey's request to extradite him.
Zaman's edition in Turkey was shut down by the government after the failed coup, in which Gulen denies involvement.
Zaman, critical of Erdogan, now has editions in Romania and Bulgaria. Zaman Romania said Demirkaya has lived in Romania for two years with his wife and son, "writing about the abuses of power in Ankara."
Cristian Preda, an independent Romanian lawmaker in the European Parliament, called on the justice minister to halt the extradition process, saying Romania had "international commitments not to extradite citizens to countries where human rights are endangered."
"Turkey is one such country," Preda said in a statement, adding that if the government extradites Demirkaya "it (will be) disqualified all over the European Union."
Copyright 2019 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.