Minnesota U.S. Sen. Amy Klobuchar joined a fast growing chorus of Senate Democrats Tuesday urging U.S. Sen. Bob Menendez to resign in light of the New Jersey Democrat's indictment last week in a federal corruption case.

"I don't believe he is going to resign," Klobuchar said in a phone interview with the Star Tribune. "I believe he should resign."

Only a small number of Senate Democrats had called for Menendez to resign as of Monday, but the number started growing rapidly Tuesday morning.

A news release from the U.S. Attorney's Office of the Southern District of New York details allegations that Menendez and his wife "accepted hundreds of thousands of dollars of bribes," from three people "in exchange for [the senator's] agreement to use his official position to protect and enrich them and to benefit the Government of Egypt."

Menendez has defended himself, and said during a public statement to reporters Monday, "I firmly believe that when all the facts are presented, not only will I be exonerated, but I still will be New Jersey's senior senator."

Klobuchar labeled Menendez's alleged conduct "a breach of trust."

"It's egregious conduct, as documented in the complaint," Klobuchar said. "It goes to the core of our job as senators and it's a violation of that trust."

At the time of the indictment, Menendez was serving as chair of the Senate's foreign relations committee. The Democratic leader of the U.S. Senate noted in a news release after the latest indictment that Menendez has "temporarily" stepped away from leading the panel.

Klobuchar made no mention of wanting to see Menendez resign when her office was asked before Tuesday to comment. She said in her earlier statement that "these are very serious charges. In addition to the ongoing federal criminal case laid out by prosecutors, these facts and the evidence must also be immediately investigated by the U.S. Senate Ethics Committee. No one is above the law."

On Tuesday, Klobuchar continued to emphasize an ethics investigation, saying "that is the way the Senate can decide this issue, which can happen separate and apart from the ongoing criminal case."

The chamber's ethics committee released a statement on the day Menendez's indictment became public.

"Absent special circumstances, it has been the long-standing policy of the Committee to yield investigation into matters where there is an active and ongoing criminal investigation or proceeding so as not to interfere in that process," the statement said.

Fellow Democratic Sen. Tina Smith said in a statement of her own Monday that "these are serious charges, but as I have always said, everyone is entitled to due process."

Smith said on social media Tuesday morning she'd tested positive for COVID. Asked Tuesday about Smith's stance on Menendez, a spokesperson pointed to the earlier statement.

Menendez was indicted in a different bribery case in 2015 that resulted in a mistrial.