Re-commit to collective defense, NATO head tells France

NATO's secretary general on Monday called on France to re-commit itself to the alliance's doctrine of collective defense.

Ahead of Tuesday's summit in London, Jens Stoltenberg told German public broadcaster ARD that NATO is "by far the strongest military power in the world" as a result of Article 5 in its charter which states that an "armed attack" against one or more members in Europe or North America shall be considered an attack against all members.

Stoltenberg stressed that all allies, including France, must abide by their "contract obligation".

Article 5 is the "heart of NATO," stressed Stoltenberg, adding that no potential adversaries would attack NATO members as long as they knew that aggression towards any ally would provoke retaliation from the entire alliance.

NATO heads of state and government will arrive for a two-day summit in the U.K. beginning on Tuesday that will mark the alliance's 70th anniversary.

The summit is expected be overshadowed by recent criticism of NATO by French President Emmanuel Macron who called NATO "brain dead", triggering harsh criticism by fellow member states, including Germany.

Stoltenberg urged NATO's 29 member states to overcome their differences when it comes to handling the situation in northern Syria.

On Russia, Stoltenberg called for a policy of combined deterrence and dialogue.

Describing Russia as NATO's "biggest neighbor", he said the alliance needed to talk to Moscow in order to improve relations.

He underlined that even in the absence of improved ties, NATO must "manage" a difficult relationship with Russia.