Turkish President Recep Tayyip Erdoğan is frustrating the U.S. and its allies by opposing the bid by Sweden and Finland to join NATO.

The position is complicating the message of unity the Biden administration wants to send to Moscow over its invasion of Ukraine.

The bids by Sweden and Finland to join the military alliance are historic — and a big defeat for Russia, which does not want them added to the group. The fact that their decision to do so is the result of the Russian war is a point that has been highlighted by U.S. officials.

But the diplomatic victory over Moscow is clouded by Erdoğan’s opposition over charges that the Nordic countries harbor Kurdish terrorist groups.

NATO members must unanimously agree to accept the members.

There are whispers that Ankara is looking for something — such as U.S. fighter jets — to give its blessing.

Erdoğan will talk with Finnish officials on Saturday and has kept the door open to a shift, telling reporters that “we will continue all these discussions for the sake of not interrupting diplomacy.”

Read more: The Hill