BRUSSELS—NATO’s 30 allies signed an accession protocol for Finland and Sweden on Tuesday, allowing them to join the nuclear-armed alliance once parliaments ratify the decision, the most significant expansion of the alliance since the 1990s.
The signing at NATO headquarters follows a deal with Turkey at last week’s NATO summit in Madrid, where Ankara lifted its veto on the Nordic membership bids following assurances that both countries would do more to fight terrorism.
