European companies are ramping up security around pipelines and energy prices are climbing again as the suspected sabotage of two pipelines that deliver natural gas from Russia underscored the vulnerability of Europe's energy infrastructure and prompted the EU to warn of possible retaliation.

Some European officials and energy experts have said Russia is likely to blame for any sabotage — it directly benefits from higher energy prices and economic anxiety across Europe — although others cautioned against pointing fingers until investigators are able to determine what happened.

Russia has sharply curtailed natural gas shipments to Europe in retaliation for sanctions that the West put in place after its invasion of Ukraine. On Wednesday, Russian energy giant Gazprom increased the pressure, threatening on Twitter to cease dealing with a Ukrainian company that controls one of the two remaining pipelines that ship Russian gas to Europe.

Coming on top of the apparent sabotage to the Nord Stream gas pipelines, "that means a major escalation and readiness to escalate," said Agata Loskot-Strachota, senior fellow in energy policy at the Center for Eastern Studies in Warsaw.

Seismologists say explosions rattled the Baltic Sea before unusual leaks were discovered Tuesday on the two underwater pipelines running from Russia to Germany.

"All available information indicates those leaks are the result of a deliberate act," EU foreign policy chief Josep Borrell said in a statement on behalf of the bloc's 27 members. "Any deliberate disruption of European energy infrastructure is utterly unacceptable and will be met with a robust and united response."