The EU is worried that the situation in Syria, where dozens of Turkish troops were killed by regime air strikes, could descend into all-out war, foreign policy chief Josep Borrell tweeted on Friday.

“There is a risk of sliding into a major open international military confrontation. It is also causing unbearable humanitarian suffering and putting civilians in danger,” he said.

The EU urged a rapid de-escalation and “will consider all necessary measures to protect its security interests,” he said, adding that the bloc was in contact with “all relevant actors.”