WASHINGTON -- The Senate Ethics Committee has an eye on the allegations surrounding New Jersey Sen. Bob Menendez, the panel’s top Republican indicated, as news reports show that Menendez used a public hearing to advocate for a business tied to Salomon Melgen, a South Florida eye doctor now under federal investigation.

"We are aware of the news reports regarding the FBI raid on Dr. Melgen’s office. The Ethics Committee will follow its established procedures in this matter," Sen. Johnny Isakson, a Georgia Republican, said in a statement. The Washington Post first reported Isakson’s comments and wrote that a review is under way. Isakson is the committee's vice chair.

The ethics committee can start a preliminary inquiry based on “virtually any source,” according to its Web site, including news reports.

Meanwhile, new stories show that Menendez, a Democrat, prodded U.S. officials to help one of Melgen’s businesses, urging the Commerce department to intervene with officials in the Dominican Republic to help a Melgen business interest there, the New York Times and Miami Herald reported. Menendez urged the action in a Senate Foreign Relations Committee subcommittee hearing he chaired in July.

Melgen, a friend and significant donor to Menendez, had a stake in a firm that had a contract to X-ray cargo at Dominican ports, but had trouble getting the contract enforced, the papers wrote. The deal may have been worth $500 million, the Times wrote. Menendez aides told the papers that he frequently advocates for American business interests. Menendez has been chair of the Western Hemisphere subcommittee on the foreign relations committee, until taking over as head of the full committee earlier this week.

The new articles add to the ethics questions that also include Menendez’s long-delayed repayment of $58,500 for two trips on Melgen’s private plane in 2010. He did not report the trips or pay for them for more than two years, and then did so only after an ethics complaint was lodged by New Jersey Republicans.

That apparent violation of Senate rules alone could be damaging, but the new stories hint at even deeper ties between Menendez and Melgen and questions about whether the Senator has tried to use his influence to help the doctor, a friend and donor.

While other issues have garnered more headlines, the ethics questions are the ones that are most documented and, as of now, the most substantiated.

Conservative Web sites have also forwarded a story that Melgen flew Menendez to the Dominican Republic to meet prostitutes, some said to be underage, an accusation Menendez has firmly denied as “false.”

“These are nameless, faceless anonymous allegations, you should find out who that is,” Menendez told television crews who questioned him Thursday night. He did not answer further questions.

The main source of the prostitution allegations is an e-mailer whose identity and knowledge of the events he cites has never been publicly verified. Officials at an independent ethics group that exchanged messages with the accuser have cast doubts on his claims and veracity.