A third allegation was leveled against U.S. Supreme Court Justice nominee Brett Kavanaugh on Wednesday, further complicating his approval process in the U.S. Senate.

The latest allegation, made by Julie Swetnick, said Kavanaugh frequented parties where boys would intentionally intoxicate girls with alcohol before making sexual advances.

Swetnick, who went to a high school close to Kavanaugh's, said she was the victim of rape in one such setting where Kavanaugh was present, stopping short of directly linking the nominee to her ordeal.

The allegations also involved Mark Judge, a high school friend of Kavanaugh's who have come out in his defense from earlier allegations.

"During the years of 1981-1982, I became aware of efforts by Mark Judge, Brett Kavanaugh and others to 'spike' the 'punch' at house parties I attended with drugs and/or grain alcohol so as to cause girls to lose their inhibitions and their ability to say 'no'," Swetnick said in a written testimony.

The testimony also stated that Judge and Kavanaugh would intoxicate girls so "they could be 'gang raped' in a side room or bedroom by a 'train' of numerous boys."

"I have firm recollection of seeing boys lined up outside rooms at many of these parties waiting for their 'turn' with a girl inside the room," the testimony said, adding these boys included Judge and Kavanaugh.

The testimony also alleged that earlier claims made by Kavanaugh during a televised interview about remaining sexually innocent during high school years was "false and a lie."

The Senate Judiciary Committee has begun reviewing the graphic allegations, which were denied by Kavanaugh, who said the accusations were "ridiculous and from the twilight zone."

"I don't know who this is and this never happened," he said.

According to the testimony, Swetnick identified herself as a resident of Washington D.C. who has held various government jobs, including with the U.S. departments of Defense, Treasury, and Homeland Security, among others.

Swetnick also said she has held secret-level security clearance for the departments of State and Justice.

The allegation emerged just one day before the Senate Judiciary Committee is set to hear a previous allegation from another woman who said she had been sexually attacked by Kavanaugh during a high school party.

Another allegation was reported by U.S. media that accused Kavanaugh of revealing his private parts to a girl while studying at Yale University.

The Republican-controlled panel has indicated that it will vote on Kavanaugh's nomination on Friday, which will decide the nature of his recommendations going into a floor vote.

Although the Republican leadership has expressed confidence in Kavanaugh's approval, several Republican senators have expressed concerns over the allegation. It would take two opposing Republican votes to sink Kavanaugh's nomination.

The floor vote can take place as early as next week, according to a senior Republican senator.