Updated with new comments from Sen. Menendez below.

New Jersey Sen. Bob Menendez denied allegations reported online that he used prostitutes in the Dominican Republic, issuing a statement Wednesday afternoon after the FBI raided the offices of a friend also tied to the accusations.

"Any allegations of engaging with prostitutes are manufactured by a politically-motivated right-wing blog and are false," said a statement from Menendez's office.

The Democrat was forced to respond to the issue after FBI agents raided the offices of a financially troubled West Palm Beach, Fla. eye doctor Tuesday night who has faced accusations involving ties to Menendez.

The agency hauled away items from Dr. Salomon Melgen’s medical offices in several vans late Tuesday, the Miami Herald reported. The FBI would only confirm that “we are conducting law enforcement activity in the general vicinity of 2521 Metrocentre Blvd,” – the address of one of Melgen’s offices. "No further comment/information at this time."

Melgen, a prominent donor to Menendez and other Democrats, has an outstanding IRS lien of $11.1 million for taxes owed from 2006 to 2009, according to records filed with the Palm Beach County recorder’s office. A previous IRS lien for $6.2 million was released in 2011, the Herald wrote.

It was unclear Wednesday whether the FBI investigation had to do with Melgen's financial dealings or with prostitution.

The only publicly known ties between Menendez, Melgen and prostitution have come from reports on the conservative online publication the Daily Caller and a tipster who has communicated with an ethics group, the FBI and at least one reporter, but the accuser does not appears to have spoken to these investigators in person or on the phone, despite repeated requests for phone conversations or meetings.

Until today, the story has been almost entirely advanced by the Daily Caller.

UPDATED - 1:50 p.m.: Menendez's office issued this statement Wednesday afternoon:

"Dr. Melgen has been a friend and political supporter of Senator Menendez for many years. Senator Menendez has traveled on Dr. Melgen’s plane on three occasions, all of which have been paid for and reported appropriately.

Menendez has previously called the allegations involving prostitution “fallacious.”

The head of an independent ethics group in contact with the accuser told the Inquirer she became "increasingly skeptical" about the claims, noting that the accuser refused repeated requests to discuss the issue by phone and only came forward with four-year-old allegations in the midst of Menendez's re-election campaign. At the same time, the group's leader said reporters told her that Republican operatives were pushing the Menendez-prostitution link.

The Daily Caller has raised accusations that Menendez, with Melgen’s help, has visited prostitutes in the Dominican Republic, including some alleged to be underage. In November the site interviewed two women who said they were prostitutes who had sex with Menendez. Their faces were blurred so as to make them unidentifiable.

Last week the site reported on e-mails – posted on a separate Web site, whose ownership is unclear – that appear to be between the FBI and a source going by the name Peter Williams who has claimed to have knowledge of Menendez and Melgen’s activities.

In the e-mails an FBI agent says that most of Williams’ information is true, but does not specify which information. The FBI e-mails posted online do not appear to specifically mention Menendez. The Herald, citing sources familiar with the investigation, reported that the e-mails are real.

They show that Williams, over the course of at least five months, refused repeated requests to speak to the FBI or provide details about the prostitutes involved. The last e-mail exchange posted online was from late December. Reached by phone earlier this week, the agent, Regino Chavez, refused to comment.

Williams has also refused to speak to reporters and ethics investigators looking into the accusations.

He contacted Citizens for Responsibility and Ethics in Washington (CREW), a watchdog group, in the spring of 2012, saying he had information about Menendez’s visits to see prostitutes in 2008. He did not initially say they were underaged, but later added that detail. He sent detailed e-mails, but after months of contact Williams refused repeated requests to have phone conversations with CREW, according to its executive director, Melanie Sloan.

CREW passed his information on to the FBI and ABC News. Williams also refused requests to speak with ABC. He has not responded to requests for comment from the Inquirer.

“CREW took the allegations very seriously but there is something very suspicious about a source who repeatedly and for months refused to speak by phone to either us, other news outlets or the FBI,” Sloan said.

She said she grew “increasingly skeptical” about Williams’ claims, adding it was “odd” that he would come forward with allegations from 2008 in the midst of Menendez’s re-election campaign.

“If you really wanted Menendez brought to justice, you would be cooperating,” Sloan said.

The story, though, was kept alive by the Daily Caller and the raid Tuesday has blown the issue into the open. It comes just as Menendez assumes a prominent role in Washington, as one of a handful of Senators pushing for immigration reform and the likely chairman of the Senate Foreign Relations Committee.

The Inquirer called Melgen Tuesday afternoon, before the raid, but he did not respond that message. Efforts to reach him Wednesday were not successful.

Melgen and his relatives are heavy Democratic donors. They gave 15,000 to Menendez in 2011 and $30,000 to the New Jersey Democratic State Committee in 2012, according to the Center for Responsive Politics.

They started donating to Menendez at least as early as 1998, according to Federal Election Commission records.

Separately, a North Jersey man pleaded guilty Tuesday to steering $21,400 of illegal campaign contributions to Menendez on behalf of the donor's politically-connected brother.