Nordic-Baltic countries and Poland have pledged to step up support for Ukraine, including making more ammunition available to strengthen deterrence and defense against hybrid attacks.
The leaders of Denmark, Estonia, Finland, Latvia, Norway, Poland, and Sweden, who met near Stockholm on November 27, also said they were ready to step up sanctions against Russia and backers of its Ukraine invasion and discussed an investigation into the severing of undersea communication cables earlier this month in the Baltic Sea.
"Together with our allies, we are committed to strengthening our deterrence, and defense, including resilience, against conventional as well as hybrid attacks, and to expanding sanctions against Russia as well as against those who enable Russia's aggression," the leaders said a statement.
The leaders met for talks covering transatlantic relations, regional security cooperation, and a common policy on the war in Ukraine. The meeting was the first of the Nordic-Baltic heads of government since 2017. Poland attended for the first time.
Ahead of the meeting Polish Prime Minister Donald Tusk proposed joint monitoring of the Baltic Sea by the navies of the Baltic states following damage to two undersea communication cables that is being investigated as a hybrid attack.
"Baltic air policing already exists for the airspace over the Baltic Sea," Tusk said. "I will convince our partners of the necessity to immediately create an analogous formula for the control and security of the Baltic Sea waters, a naval surveillance," he added.
The underwater cables -- one linking Finland and Germany and the other connecting Sweden to Lithuania -- were damaged on November 17-18, prompting suspicions of sabotage.
SEE ALSO: Danish Military Keeps Watch On Chinese Ship Suspected Of Baltic Cable SabotageSweden, Germany, and Lithuania have all launched investigations, but the cause of the damage is still unknown.
Finnish police have said they believe the incident was caused by a Chinese ship dragging its anchor, and Swedish investigators have focused on the Chinese cargo ship Yi Peng 3, which is thought to have passed both locations at the times of the cable breaks.
The ship now sits idle in international waters but inside Denmark's exclusive economic zone.
Sweden has asked the vessel to return to Swedish waters to help facilitate the investigation, Prime Minister Ulf Kristersson said on November 26, but he stressed he was not making any accusations.
Kristersson told a press conference he was hopeful China would respond positively to the request to move the ship to Swedish waters.
"From the Swedish side we have had contact with the ship and contact with China and said that we want the ship to move towards Swedish waters," Kristersson said.
A Chinese Foreign Ministry spokeswoman said communications with Sweden and other relevant parties had been "unobstructed."
Mao Ning said at a regular news briefing on November 27 that China has shown "consistent support" in working with other countries to maintain the security of international undersea cables and other infrastructure.
Yi Peng 3 left the Russian port of Ust-Luga on November 15. Russia last week said suggestions it had anything to do with the breaches were "absurd."
The Wall Street Journal reported on November 27 that the ship has been surrounded by European warships in international waters for a week. Investigators suspect the crew of the Yi Peng 3, which is loaded with Russian fertilizer, deliberately severed the cables by dragging its anchor for more than 160 kilometers, the newspaper reported.
The probe centers on whether the captain of the ship was induced by Russian intelligence to carry out the sabotage, the report said.