Two female participants in the District’s summer youth employment program were allegedly victims of sexual assault while at work this week, and one man has been charged, authorities said.

One of the incidents occurred Wednesday at the headquarters of the Department of Employment Services and the other occurred Friday, at a public high school that was reportedly undergoing renovation, according to authorities’ accounts.

The administration of Mayor Vincent C. Gray issued a statement expressing outrage over the reports.

“These alleged acts are extremely alarming, disappointing and reprehensible,” the mayor said in the statement. “We will not tolerate, for a moment, the victimization of our young people in the” summer job program “who have the right to expect this to be a wholesome, healthy and enriching work experience.”

The Wednesday incident occurred at the employment services department’s headquarters at 4000 Minnesota Ave. NE, officials said.

Assistant police chief Peter Newsham said the victim was a 17-year-old, and a spokesman for the employment services department said she was employed at the headquarters as part of her participation in the youth jobs program.

Officials said Thomas Nelson, 54, of Northeast Washington, who was employed at the headquarters as a file clerk, was arrested and charged with second-degree touching of a minor by a person in a position of authority.

In the Friday incident, a 19-year-old woman alleged that she was touched inappropriately by a construction contractor at Anacostia Senior High School in Southeast Washington, Newsham said. No arrest has been reported in that incident, which authorities said remained under investigation.

The summer jobs program began June 27, with an initial enrollment of 12,000 participants; it will be expanded to include a total of 14,126 participants at almost 1,100 sites, an employment services spokesman said.

The mayor’s office said youth employment staff members will reemphasize to participants the safety measures they were taught, as well as he need to always report improper or questionable behavior.