EU Foreign Policy chief Josep Borrell believes Tuesday’s damage to the Nord Stream pipelines was deliberate sabotage, and has warned it will be met with a “robust” response.

Reports emerged on Tuesday of explosions from under the Baltic Sea with unusual leaks discovered on the Nord Stream 1 & 2 pipelines.

Danish PM Mette Fredriksen said that authorities insist it was a deliberate act, but added that there was “no information indicating who could be behind it,” despite Polish MEP Radoslaw Sikorski insinuating on Twitter that the US was responsible.