Gas from Nord Stream 1 and 2 pipelines, running from Russia to Germany, leaked into the Baltic Sea. A pressure drop was detected in both the lines Monday.
Danish authorities advised ships not to enter within five nautical miles of Bornholm island as authorities try to determine the cause of the leaks.
Both Nordstream 1 and 2, now-defunct pipelines, were filled with natural gas when a sharp pressure drop was detected.
Officials are unclear about the cause of the leaks but said that it would not affect the security of gas supply to Germany and Denmark.