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.

Germany’s defense minister said damage to two fiber-optic cables on the sea floor appeared deliberate, but a culprit was not known.

U.S. allies warned of "hybrid warfare" Tuesday after two undersea communication cables were severed in the Baltic Sea, raising suspicions that they may be the latest acts of sabotage targeting the West as it clashes with Russia.

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.