Leaders of Baltic Sea nations and NATO's chief have confirmed that they will step up measures to protect critical undersea infrastructure in the region.

The decision comes after a series of incidents that damaged undersea power lines, communication cables and other facilities in the Baltic. Some suspect these are sabotage attempts involving Russia.

Leaders from eight countries and NATO Secretary General Mark Rutte met in the Finnish capital, Helsinki, on Tuesday to discuss their response.

Statements from their governments and others say the countries will work with NATO to increase maritime patrols by ships and aircraft in the area, aiming to monitor suspicious vessels.

They also affirmed that they will identify further measures in accordance with international law to respond effectively to similar incidents.

Additionally, the leaders agreed to strengthen surveillance of vessels that evade Western sanctions by transporting Russian crude oil.

Rutte told reporters after the meeting that potential threats to infrastructure will have consequences, including possible boarding, impounding and arrest.

The talks appeared to underscore unity among the participating nations and NATO.