WASHINGTON Embattled U.S. Senator Bob Menendez on Thursday is expected to address his Democratic colleagues, more than half of whom have called for him to resign, the day after he pleaded not guilty to federal charges of accepting bribes.

A total of 27 senators in the 51-member caucus - Democrats and three independents who typically vote with them - have called for Menendez's resignation, including No. 2 Senate Democrat Dick Durbin, the head of the Senate Democrats' campaign arm, Gary Peters, and Menendez's fellow senator from New Jersey, Cory Booker.

Chuck Schumer, the Senate's top Democrat, said on Wednesday Menendez's behavior fell below the standard appropriate for a senator, but stopped short of calling for him to resign.

Prosecutors have said Menendez and his wife, Nadine Menendez, accepted gold bars and hundreds of thousands of dollars in exchange for using their influence to interfere with law enforcement probes of three New Jersey businessmen and aid the Egyptian government.

They pleaded not guilty in court on Wednesday. Menendez said on Monday he would remain in office and fight the charges.

Menendez's Senate seat is in play in the 2024 elections. Though New Jersey has not elected a Republican to the Senate since 1972, his legal troubles could pose problems for his party, which is trying to maintain its narrow control of the chamber. Menendez has drawn one challenger to the seat so far.

(Reporting by Richard Cowan, Makini Brice and Moira Warburton; Editing by Jamie Freed)