he U.S. Justice Department is preparing criminal corruption charges against New Jersey Democratic Senator Robert Menendez, CNN reported on Friday.

Citing people briefed on the matter, CNN said the charges center on allegations that the senator used his office to promote the business interests of a Democratic donor and friend in exchange for gifts.

CNN said Attorney General Eric Holder has given the green light for prosecutors to proceed with charges and an announcement could arrive in coming weeks.

A representative for Menendez could not immediately be reached for comment.

Justice Department officials did not immediately respond to a request for comment.

Menendez is the top Democrat on the Senate Foreign Relations Committee.

Federal authorities have probed Menendez's relationship with Florida ophthalmologist Salomon Melgen, a Democratic donor who has been accused of overbilling the Medicare program.

CNN said the government's case focuses on Melgen and, in part, on plane trips that Menendez took in 2010 to the Dominican Republic as a guest of Melgen.

Prosecutors also are focusing on whether Menendez advocated for Melgen's business interest in a Dominican Republic government contract for a port screening equipment, CNN said.

spokeswoman for U.S. Senator Robert Menendez said on Friday that the New Jersey Democrat's actions have all been "appropriate and lawful," after reports that the U.S. Department of Justice was preparing corruption charges against him.

Menendez was one of several senators who introduced legislation last week requiring congressional review of any deal with Iran over its nuclear program.