Democratic Senator Bob Menendez has been charged alongside his wife with taking bribes from three New Jersey businessmen.
It has prompted some within his party, including the Democratic governor of Mr Menendez’s state of New Jersey, to publicly urge him to step down.
But in a press conference on Monday, his first public remarks since being charged, Mr Menendez said: "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.”
Prosecutors allege the elected official accepted gold bars and hundreds of thousands of dollars in cash in exchange in exchange for political favours.
But he has claimed his stashing of nearly half a million dollars in cash at home stemmed from his family’s fear about having their belongings confiscated in Cuba.
Federal agents who searched his home last year found more than $480,000 in cash (£393,000) in envelopes, along with 13 bars of gold bullion.
Prosecutors allege that the senator made online searches for how much a bar of gold is worth, according to an indictment setting out the charges.
“This may seem old fashioned, but these were monies drawn from my personal savings account based on the income that I have lawfully derived over those 30 years," he said.
Mr Menendez has stepped down temporarily from his role as chairman of the powerful Senate Foreign Relations Committee.
On Monday, Sherrod Brown became the second Senate Democrat to call for him to resign, saying in a statement: “Senator Menendez has broken the public trust and should resign from the US Senate."
Senator John Fetterman, a Pennsylvania Democrat, on Saturday had earlier urged Menendez to resign in a post on Twitter.
Mr Menendez, his wife Nadine Menendez and the businessmen are expected to appear in Manhattan federal court on Wednesday.
The charges he and his wife face carry a sentence of up to 45 years in prison, though judges in these types of cases usually impose less than the maximum possible sentence.