US Senator Bob Menendez has been accused in a new federal indictment of accepting bribes from Qatar - the second foreign country he is alleged to have improperly aided.
The latest allegations accuse him of a corruption scheme from 2021-23.
A lawyer for the New Jersey senator said the justice department claims were "baseless" and "bizarre conjectures".
Mr Menendez, a Democrat, pleaded not guilty in October to charges alleging he acted as an illegal agent of Egypt.
He has faced growing calls to resign, including from his own party, but has so far refused to step aside.
The indictment unveiled on Tuesday alleges that Mr Menendez accepted gifts, including tickets to see car races, in exchange for comments praising the Qatari government.
The document does not contain any new charges, but includes new details of his and the alleged crimes of his wife - Nadine Menendez.
Mrs Menendez, who is also charged in the same alleged bribery and extortion scheme, has also pleaded not guilty.
Three New Jersey businessman named in the case have denied charges as well.
The latest allegation extends the alleged plot by one year, and it includes his time as the chairman of the Senate Foreign Relations Committee - a post he quit after the initial charges were filed in September.
Mr Menendez, 70, has denied any wrongdoing.
The new indictment claims he assisted one of the accused businessman - Fred Daibes - by making public comments in favour of Qatar in order to help him secure an investment.
An attorney for Mr Daibes, Tim Donohue, told OceanNewsUK his client had no immediate comment.
After introducing Mr Daibes to an investor who is a member of the Qatari royal family, prosecutors say Mr Menendez "made multiple public statements supporting the Government of Qatar".
He then supplied the statements to Mr Daibes to use as a tool to convince the unnamed Qatari royal to invest in his New Jersey real estate project.
"You might want to send to them. I am just about to release," Mr Menendez allegedly texted Mr Daibes in August 2021, referring to a press release that contained favourable comments about Qatar.
About a month later, the senator and Mr Daibes attended an event in New York hosted by the Qatari government.
Days later, the indictment says, Mr Daibes sent the senator photographs of watches ranging in price from $9,990 to $23,990 (£7,900 to £19,000), asking Menendez: "How about one of these?"
In 2022, ahead of the meeting with Mr Daibes and the Qatari investor in London, Mr Menendez allegedly texted both of them: "Greetings, I understand my friend is going to visit with you on the 15th of the month.
"I hope that this will result in the favorable and mutually beneficial agreement that you have both engaged in discussing."
Among the benefits Mr Menendez received from the Qataris, the indictment alleges, were tickets to a Formula One Grand Prix race in Miami, Florida.
It also claims that one day after returning from a trip to Qatar and Egypt and being picked up at the airport by Mr Daibes driver, the senator performed a web search for "how much is one kilo of gold worth".
A search of the Menendez house in June 2022 discovered, among other things, two one-kilo gold bars that the government says were provided as part of the bribery plot.
Agents also discovered hundreds of thousands of dollars in cash that bore Mr Daibes' fingerprints and DNA.
Adam Fee, a lawyer for Mr Menendez said in a statement, "the government's new allegations stink of desperation".
He said the prosecutors' claims are all "based on routine, lawful contacts between a Senator and his constituents or foreign officials".
"At all times, Senator Menendez acted entirely appropriately with respect to Qatar, Egypt, and the many other countries he routinely interacts with," the lawyer added.
