BUDAPEST (Reuters) - A bipartisan U.S. Congressional delegation will visit Hungary on Sunday as pressure grows on Budapest to ratify Sweden’s NATO membership when parliament reconvenes after its winter break.

Hungary is the only NATO country not to ratify Sweden’s application, a process that requires the backing of all members, souring relations with the United States and raising concerns among its allies.

Sweden applied to join NATO in May 2022 in a historic shift in policy prompted by Russia’s invasion of Ukraine.

Hungarian Prime Minister Viktor Orban, who has better ties with Russia than other EU states and most NATO members, says his government backs Sweden joining the alliance, but the legislation nevertheless remains stranded.