“Sen. Menendez has traveled on Dr. Melgen’s plane on three occasions, all of which have been paid for and reported appropriately,” Menendez's office said in a statement.

The Daily Caller has also reported that Menendez solicited prostitutes during the trips, although Menendez has vehemently denied that charge.

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

"There a lot that’s said and covered, but I for one know Bob as a very capable United States senator, and I’m sorry to see him in this position," Lautenberg said. "But I can’t give you anything more. Don’t want to. Don’t know to."

White House press secretary Jay Carney also declined to comment when asked about the reports on Thursday.