The Nordic countries should tighten diplomatic and military ties by pooling resources and issuing a mutually binding security guarantee, a report commissioned by the five governments said Monday.

Pointing to new challenges facing the region -- including the shrinking Arctic ice cap and soaring prices for modern technology -- the report's author, former Norwegian foreign minister Thorvald Stoltenberg, offered 13 proposals to strengthen ties among the five.

"The Nordic governments should issue a mutual declaration of solidarity in which they commit themselves to clarifying how they would respond if a Nordic country were subject to external attack or undue pressure," said Stoltenberg, who is also the father of Norway's current prime minister, Jens Stoltenberg.

The five countries include Norway, Sweden, Denmark, Finland and Iceland.

Such a declaration would be a first in a region where only Norway, Denmark and Iceland are covered by NATO's mutual assistance guarantee, while non-members Sweden and Finland remain unaligned.

Norway and Iceland are also not members of the European Union.

"The declaration would have to be made in a form that would ensure that it did not come in conflict with the Nordic countries' existing UN, EU and NATO obligations," the report said.

The Nordic countries should also establish a polar orbit satellite linked to a joint maritime monitoring system that could provide "frequently updated real-time images of the situation at sea," as well as a network against cyber attacks, the report said.

It also called for establishing a Nordic "stabilisation task force," including both civilian and military personnel working with a mandate from the United Nations or other international bodies, a war crimes investigation unit and a joint civilian disaster response unit.

In addition, the five countries should consider setting up joint embassies and tighten military cooperation when it comes to transportation, exercises and equipment purchases.

The report was handed over to the five governments and is set to provide a basis for discussion during a foreign ministers' meeting in Reykjavik during the first half of this year.