STORY: The comment came hours before the summit in Madrid as Turkey voiced unexpected objections to the two Nordic countries' membership bid, which if successful would be the biggest shift in European security in decades.
New membership to the U.S.-led military alliance requires unanimity among the existing members and a Turkish veto would threaten to overshadow a summit striving for unity as Russia wages war in Ukraine.
Ankara's main demands are for the Nordic countries to stop supporting Kurdish militant groups present on their territory, and to lift their bans on some sales of arms to Turkey.
Stoltenberg told reporters other issues would be on the table during the summit.
"The Madrid Summit will be a pivotal summit. We will agree a new strategic concept - the Madrid strategic concept - that will be the blueprint for NATO in a more dangerous and unpredictable world," he said.