British Prime Minister Boris Johnson on Wednesday said he had agreed new deals with Sweden and Finland to bolster European security, pledging to support both countries' armed forces should they come under attack, APA reports citing RIA.

The agreements, described by Britain as "a step-change in defence and security cooperation", will go some way to assuage fears in Finland and Sweden over threats made by Russia should either nation decide to join NATO. 

"What we are saying, emphatically, is that in the event of a disaster or the event of an attack upon Sweden, then the UK would come to the assistance of Sweden with whatever Sweden requested," Johnson said after meeting Swedish Prime Minister Magdalena Andersson.

Johnson would not say whether the UK would send troops to Sweden in the event of an attack.