"NATO supports Ukraine and will continue to provide political and practical support to the country as part of the established cooperation," the statement said.
The Alliance calls on Russia to ensure unimpeded access to Ukrainian ports and freedom of navigation, as well as to immediately release the sailors.
NATO stressed that they will continue to monitor the situation.
Earlier, NATO Secretary General Jens Stoltenberg discussed with the Ukrainian President Petro Poroshenko the introduction of martial law in the country.
On November 25, three vessels of the Ukrainian Navy illegally crossed the Russian border and were detained.