The Hungarian government refused a meeting with US senators in Budapest about Sweden's accession to NATO, according to media reports.
Jeanne Shaheen, Democrat senator for New Hampshire and co-Chair of the Senate NATO Observer Group, expressed her disappointment in a news conference on Sunday over the move, the Budapest Times reported.
She recalled that Hungary was the last NATO member to not ratify Sweden's membership.
Hungarian Prime Minister Viktor Orban previously said that the parliament would ratify the bid in the spring session.
The US delegation said they will submit a resolution to Congress to urge Hungary to ratify.
Senators Thom Tillis and Chris Murphy are also part of the delegation.
Hungary became the only NATO ally that has yet to approve Sweden's membership in the alliance after Turkish parliament ratified the Nordic country's application on Jan. 23.
Admission of a new member requires the unanimous support of all NATO members.
Sweden and Finland applied for NATO membership in May 2022 following the start of Russia's war on Ukraine earlier that year.
Finland joined the alliance as its 31st member in April 2023.
