EU leaders at a summit on Thursday in Brussels will consider the toughest package of sanctions against Russia that the European Union has ever adopted, said the head of EU diplomacy Josep Borrell.

“We will respond in the most decisive manner. The head of the European Council has called an EU summit this evening. At the summit, political consent will be obtained to adopt the most powerful package of sanctions that we have ever applied,” he told reporters.

The head of EU diplomacy also promised that he would be in contact with EU partners around the world to guarantee a unified response and appeal to Russia. “The Russian leadership will face unprecedented isolation,” he promised.