Menendez in October pleaded not guilty to charges of conspiring to act as an unregistered foreign agent for the Egyptian government and accepting hundreds of thousands of dollars from New Jersey businessmen in exchange for interfering with law enforcement probes into them.

In Tuesday's superseding indictment, federal prosecutors in Manhattan said Menendez introduced the businessman, Fred Daibes, to a member of the Qatari royal family to negotiate a multimillion-dollar investment into a real estate project. Daibes was indicted alongside Menendez and has pleaded not guilty.

Menendez's trial is set for May 6.

(Reporting by Luc Cohen and Jonathan Stempel in New York; Editing by Sandra Maler)

By Luc Cohen and Jonathan Stempel