Europea and its allies must stay united and take a firm stance against Russia, "while keeping open all possible dialogue channels" over the crisis at Ukraine's borders, according to Italy's premier Mario Draghi.
"Besides presenting a united front to Russia, both within Europe and the Atlantic Alliance, we need to maintain a firm deterrence strategy right now," Draghi said.
Draghi was speaking after European Union leaders met in Brussels on Thursday to discuss the Ukraine crisis.
"We need to be strong and not to show weakness," he underlined.
"Thirdly, we need to state clearly from the outset that we cannot renounce the core principles of the Atlantic Alliance, while at the same time keeping open all possible dialogue channels," he said.
Draghi's remarks came as US president Joe Biden warned Russia could launch an invasion of Ukraine in the coming days, but said a diplomatic solution was still possible.
For its part, Russia said reports of shelling in the Donbas region of eastern Ukraine were concerning but accused the West of hysteria over warnings of a looming invasion of the former Soviet republic.