Latvian Foreign Minister Edgars Rinkevics described leaks in the Nord Stream 1 and 2 gas pipelines as "deliberate attacks."
Three leaks were found earlier this week in the pipelines that carry gas from Russia to Europe via the Baltic Sea, in the exclusive economic zones of Denmark and Sweden off the Danish island of Bornholm.
"The sabotage of the Nordstream I and II pipelines must be classified as the most serious security and environmental incident in the Baltic Sea," Rinkevics tweeted. "It seems we are entering a new phase of hybrid war."
Rinkevics said Latvia stands in solidarity with Denmark and is ready to support the investigation in any way it can. "NATO and the EU should take this seriously and respond accordingly," he said after a phone call with his Danish counterpart Jeppe Kofod.
