German Chancellor Olaf Scholz condemned on Thursday Russia's attack on Ukraine as an unjustified and flagrant breach of international law and said Berlin would consult its partners in the G-7, NATO and the European Union.

"This is a terrible day for Ukraine and a dark day for Europe," Scholz said in a statement.

"Germany condemns in the strongest possible terms this unscrupulous act by President (Vladimir) Putin. Our solidarity goes out to Ukraine and its people," he added in a statement.

NATO to hold emergency meeting on Ukraine

NATO ambassadors will hold an emergency meeting later in the morning, a NATO official told Reuters Thursday, after Russia launched its attack on Ukraine.

Earlier, the alliance's Secretary-General Jens Stoltenberg had urged Russia to cease its military action immediately and respect Ukraine's sovereignty and territorial integrity.