Ukraine could potentially join NATO even if parts of its territory remained occupied by Russia, the alliance’s former Secretary General Jens Stoltenberg said in an interview on Oct. 4.

One of the main arguments against granting Ukraine membership at the current time is that NATO’s Article 5 mutual defense clause would immediately draw the alliance into a direct war with Russia.

But speaking to the Financial Times, Stoltenberg suggested there could be ways to get around this if the Ukrainian territory considered part of NATO was “not necessarily the internationally recognized border.”