A former Montgomery County karate instructor was sentenced Tuesday to 6½ years in federal prison for sexually assaulting two underage boys he had mentored on trips to tournaments.

Evan Burgess, 28, pleaded guilty in June to traveling in interstate commerce to engage in illicit sexual conduct for the assaults, which occurred in hotel rooms in Maryland and Long Island.

“Mr. Burgess has accepted responsibility for his conduct, and while he recognizes that his regret does little to lessen the impact of his actions on the victims in this case, he is deeply sorry for the harm that his actions have caused,” his federal public defender, Elizabeth Toplin, wrote in court documents.

Prosecutors said Burgess first met the victims, teenagers at the time of his assaults, at Destolfo’s Premier Martial Arts in Conshohocken. In both assaults, Burgess climbed into bed with the boys and performed sexual acts on them, both times as a family member of the victim slept in another bed nearby, according to prosecutors.

Separately, Burgess was accused of similar behavior by three other former students, including some who had known him since they were as young as 10 years old. Burgess was found guilty of those crimes by a Montgomery County jury in June, and sentenced to three to six years in state prison.

“The victims’ parents respected the defendant and viewed him as a positive adult mentor in their sons’ lives,” Assistant U.S. Attorney Kelly Harrell, the lead prosecutor on the case, wrote in court filings. “The defendant took advantage of this role and had the audacity to victimize his students even in the presence of other adults, inside his parents’ home while they were upstairs, and, in one instance, even in the presence of the victim’s own parent.”

She also noted that Burgess’ behavior “had a tremendous impact on the lives of the victims and their families.” One victim, Harrell wrote, blamed himself for the abuse and came to dislike karate, a sport to which he had devoted many years.

“In reality, it is the defendant who is solely responsible for his own criminal conduct,” Harrell wrote.

Burgess’ state and federal sentences will run concurrently, although he will be incarcerated in the federal prison system.

U.S. District Judge Timothy Savage also ordered him to serve 15 years of supervised release, and required him to register as a sex offender.