A general view of a NATO Defense Ministers' meeting at the Alliance's headquarters in Brussels, Belgium on June 16, 2023. (REUTERS/Yves Herman)

NATO Secretary-General Jens Stoltenberg said the ministers reviewed the plans - the first since the end of the Cold War and given impetus by the Russia-Ukraine conflict - at a two-day meeting in Brussels and were moving closer to agreeing on them.

One diplomat said Turkey had blocked approval over the wording of geographical locations, including with regard to Cyprus. There was still an opportunity to find a solution before the NATO summit in mid-July in Vilnius, the diplomat added.

Turkey's diplomatic mission to NATO said it would be wrong to comment on a secret NATO document, adding that the usual process of consultations and evaluation among allies is continuing.