Sweden says it is trying to help a Swedish-Turkish journalist held in Spain for the past six days.
Hamza Yalcin was arrested at Barcelona's El Prat airport on 3 August on an international arrest warrant requested by Turkey.
Sweden's foreign ministry says it has ensured he has a lawyer and is trying to arrange a prison visit.
His detention comes as Turkey faces criticism for its treatment of journalists after the 2016 failed coup.
In one of the most high-profile cases, 17 journalists from the leading Cumhuriyet daily are being tried on charges of aiding a terrorist organisation.
The Swedish foreign ministry said it was trying to clarify the charges against Mr Yalcin but Reporters without Borders (RSF), which campaigns for journalistic freedom, says Turkey accuses him of terrorism.
RSF accuses the Turkish government of using the state of emergency imposed following last year's attempted coup against President Recep Tayyip Erdogan to suppress criticism of the government. Dozens of journalists have been detained.
The Turkish government has also carried out a crackdown on alleged coup supporters, with more than 150,000 state employees dismissed and some 50,000 people arrested.
Mr Yalcin has lived for decades in exile in Sweden where he edits a Turkish-language online publication, Odak, which is critical of the Ankara government.
Odak, which is campaigning for his release, says he has been sentenced and then acquitted twice by the Turkish courts for anti-government activity.
Separately, campaigning is under way in France for the release of French journalist Loup Bureau, who has been held in Turkey since 26 July.
He was picked up on the Turkey-Iraq border and pictures of the YPG Kurdish militia were found on his laptop, a Turkish security source told AFP news agency.
Turkey sees the YPG as an arm of the outlawed PKK, which has fought for decades for Kurdish autonomy in south-eastern Turkey.