European officials are looking toward Russia after two submarine internet cables in the Baltic Sea were suddenly disrupted in an apparent sabotage operation, just weeks after the United States warned that Moscow was likely to target critical undersea infrastructure.

German officials said on Tuesday they believe the damage to two underwater fiber-optic cables in the Baltic Sea was an act of sabotage, but they could not speculate beyond that.

Cables connecting Finland with Germany, and Lithuania with Sweden, have been disrupted, just weeks after the United States warned that it had detected increased Russian military activity around key undersea cables.