Two Greek soldiers entered Turkish territory in March and Turkey's judiciary says it's still trying to establish whether they did so inadvertently or deliberately.
Turkey has dismissed EU Commission President Jean Claude Juncker's call for two Greek soldiers who strayed over the border to be released.
On Wednesday a court in northwestern Turkey ordered the soldiers to remain in detention after being apprehended in March.
The court ruled against a petition by the soldiers’ lawyers to release them.
The Turkish foreign ministry put out a statement on its web page on Thursday saying “With these remarks ... EU authorities lose their credibility and reliability day by day."
It added that Juncker's call, which he made whilst on a visit to Greece on Wednesday, lacked any legal basis.
The Greek soldiers were remanded in custody on March 2 for entering a prohibited military zone in Edirne, which borders Greece.
Turkey has grown angry at Greece's refusal to hand over eight Turkish soldiers who have claimed political asylum in Greece.
Athens has ruled that it cannot return the soldiers, saying they wouldn't receive a fair trial in Turkey.
The eight commandos commandeered a helicopter to flee Turkey as a coup against President Tayyip Erdogan crumbled in July 2016.
Turkey remains under a state of emergency as Erdogan's government continues a purge of thousands of suspected coup supporters from all organs of the state.
Turkey and Greece and their militaries have also been deadlocked for decades over the divided island of Cyprus.
Despite many attempts to reunify it, Cyprus remains split between a northern third administered by Turkey and the remaining two thirds which are administered by the EU state of Cyprus.