Prime Minister Ulf Kristersson, who took over the reins in Sweden two weeks ago, was speaking in Helsinki at a press conference with his Finnish counterpart Sanna Marin, whose country is applying for membership in the Atlantic alliance together with Sweden.

When asked if the two nations would accept nuclear weapons on their soil, Marin replied: "We shouldn't put any preconditions... We have decided that we don't want to close any doors for the future."

Kristersson agreed.

"You will receive exactly the same answer from me as from the Finnish prime minister", he said.

"It's very natural for Sweden and Finland to act very jointly in these matters and have exactly the same formalisation. So I have no other intention than going hand-in-hand also in this sense with Finland", Kristersson told reporters.

Both Marin and Kristersson however acknowledged that reservations could be negotiated "later".

Sweden's Social Democratic party, which was in power when Sweden submitted its membership application in May, said that it would work to express "unilateral reservations against the deployment of nuclear weapons and permanent bases on Swedish territory".

In Finland, the import, manufacture, possession and detonation of nuclear explosives is prohibited by law.

Nordic neighbours Denmark and Norway, which are already NATO members, have both refused to allow foreign countries to establish permanent military bases or nuclear weapons on their soil in peacetime.