The much-criticized nomination of businessman George Tsunis to be ambassador to Norway is facing even more opposition, now from the co-chairs of the congressional Friends of Norway Caucus.

The co-chairs – Minnesota U.S. Reps. Betty McCollum and Erik Paulsen -- are urging President Obama to withdraw Tsunis' nomination.

"In Minnesota we have a vibrant Norwegian-American population with a rich appreciation for the culture and heritage of Norway," McCollum said.

"We expect the next U.S. ambassador to possess both expertise and appreciation for Norway and its people. Unfortunately, the current nominee falls far short of this standard. I urge President Obama to withdraw his nomination immediately and instead find a new nominee who will make Norwegian-Americans proud."

McCollum, a Democrat, and Paulsen, a Republican, join both U.S. senators from Minnesota, home to the United States' largest Norwegian-American population, in opposing Tsunis.

Earlier this week, Sen. Al Franken announced he will vote against Tsunis if his nomination comes to the Senate floor. Sen. Amy Klobuchar made the same vow earlier this year.

Tsunis, who helped raise nearly $1 million for Obama's 2012 campaign, was nominated for the diplomatic post nine months ago.

During an appearance before the Senate Foreign Relations Committee in January, Tsunis bungled answers to questions and testified that he has never visited Norway. His performance drew a strong rebuke from Norwegian-Americans across the country.

Because the Senate has sole responsibility for confirming ambassadors, McCollum and Paulsen can't cast votes against Tsunis.

"While ambassadorships are often tied to political support for the President, the answers provided by nominee George Tsunis clearly demonstrate that he is unqualified for this position and may damage an important international bond if confirmed," Paulsen said.

"The President would serve the Norwegian-American community well by withdrawing Tsunis's name and nominating somebody that will help our relationship continue to grow and thrive."