In a letter to the leaders of the European Union bloc today, European Council President Charles Michel said, "It is important that we continue to unite and resolve and jointly define our collective approaches and actions."

The President of the European Council announced that the European Union would hold an emergency summit in Brussels late on Thursday on Russian "aggressive actions" against Ukraine.

He added: "I would therefore like to invite you to attend a special European Council summit on Thursday, 24 February, which will be held in a personal presence in Brussels.

The summit follows the adoption by the European Union of sanctions against Russia for declaring the independence of the Lugansk and Donetsk Republics within the Donbass region and authorizing the armed forces to send peacekeeping forces if necessary.

The European Union says that it keeps more severe sanctions in place if Russian forces "invade more territory, beyond separatist control," referring to the two Republics.

In his invitation to the summit, Michelle wrote: "The use of force and coercion to change borders has no place in the twenty-first century."

"The aggressive actions of the Russian Federation violated international law and the territorial integrity and sovereignty of Ukraine. It also undermines the European security system. "