(CNN) During an overseas trip in 2015, Rear Adm. Ronny Jackson, the White House physician, was intoxicated and banged on the hotel room door of a female employee, according to four sources familiar with the allegation.

The incident became so noisy, one source familiar with the allegation told CNN, that the Secret Service stopped him out of concern that he would wake then-President Barack Obama.

Two sources who previously worked in the White House Medical Unit described the same incident, with one former staffer telling CNN that it was "definitely inappropriate, in the middle of the night," and that it made the woman uncomfortable.

At the time, the incident was reported up the chain of command, and it is one of multiple drunken episodes involving Jackson on overseas trips, according to a source familiar.

Members of the Senate Veterans' Affairs Committee have been working through all of the allegations, but have not substantiated the claims, with little documentation available to corroborate them.

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