Four Syrians and a Turkish man have been arrested for a deadly bombing at a border crossing last month.
Fourteen people were killed and dozens wounded when a minibus exploded in the southern Turkish province of Hatay.
The five suspects have appeared in court.
Two are accused of carrying out the bombing and one of organising the attack.
“Yes, we have confirmed that they have links with Syrian officials and intelligence officials but those will be revealed during the trial period. We know that the aim of the attack was to prevent the humanitarian aid to Syria,” said Turkey’s Interior Minister Muammer Güler.
Reports in the Turkish press say those arrested have admitted being paid by people tied to Syrian intelligence agency al-Muhabberat and that police are looking for one more suspect.