The Ukrainian government has asked Norway to ban Russian fishing vessels from entering Norwegian ports, according to the Danish publication Dagbladet Borsen.

In April, Russian-flagged vessels were banned from docking at Norwegian ports as part of a new range of sanctions in response to Russia's war in Ukraine.

Fishing vessels, however, were exempted from the ban and are allowed to dock as normal for commercial and research purposes.

In a letter to Norwegian officials, Ukraine asserts that by exempting Russian fishing vessels from the ban, the boats provide Russia with a source of income to fight the war, can be exploited for smuggling, and used by Russia for intelligence purposes.

In contrast to Norway, the EU introduced a total ban on Russian ships.

Norway Ministry of Trade, Industry and Fisheries State Secretary Vidar Ulriksen said the exception is not about economics, but fisheries management.

"For Norway, it is very important to protect the sustainable management of the fish stocks in the north, and therefore Russian fishing boats have been granted an exception to the port ban," he told the newspaper.

That justification met opposition from some Norwegian officials, who are asking that the country comply with Ukraine's request.