Turkey has been involved in a dispute with Greece and Cyprus over oil and gas exploration rights in the Eastern Mediterranean for months.
Tensions escalated in August as Turkey dispatched the seismic research vessel, Oruc Reis, and warships escorting it to prospect for energy resources in an area in the sea that is disputed with Greece, infuriating Athens.
The ship was withdrawn temporarily, but was sent back on Wednesday, reigniting the tensions.
The European Union has previously threatened to impose sanctions on Turkey over the activities in the disputed waters. Greece and Cyprus also pushed for a tougher response to Turkey's natural gas exploration in disputed waters at an EU summit on Friday.
Erdogan slammed on Saturday the EU’s stance and accused the EU of “double standard,” adding the reliability of the bloc has already diminished.
"The European Union is doing the most damage to itself by becoming captive to Greece and Greek Cypriots. The reliability of the European Union has already diminished because of the double standard the bloc imposes on our country at the cost of defying all the values it has been defending to this day,” the Turkish president said.
“If the EU does not hold an unbiased stance in existing disputes in the eastern Mediterranean, this situation will be the official declaration of the end of the European Union," he added.
Underscoring Turkey’s right to the exploration of natural resources in the disputed waters, Erdogan said, "The path to achieving peace and stability in the eastern Mediterranean goes through respecting, acknowledging and handing over the rights of Turkey and Turkish Cypriots. Other than this, we will not accept bullying or games that are reaching the level of comedy."
Erdogan’s remarks came a day after the EU accused Ankara of “provocations” and “unilateral actions” in the Eastern Mediterranean Sea.