Sweden's ruling Social Democratic Party convened a parliamentary debate on Monday on the country's NATO membership, Reuters reports.

Sweden and neighboring Finland are expected to decide to apply for NATO membership in the coming days.

The Swedish Social Democrats are due to announce their decision on Sunday. Their support is seen as crucial to the NATO bid.

It is very important that the government and parliamentary parties discuss the main changes in security policy that Russian aggression brings with it, the government said. If the Social Democrats support entry, as many expect, a centre-left minority government could call a parliamentary vote on the application, but this is not formally required.

If Sweden applies and is ratified by 30 NATO member states, the Swedish Riksdag will have to approve it by vote, although this is likely to be a formality given the expected broad support in Parliament.