The D.C. Police Department identified the missing teens on Twitter as: Audrey Mwamikazi, 17; Aristide Irambona, 18; Kevin Sabumukiza, 17; Don Ingabire, 16; Nice Munezero, 17; and Richard Irakoze, 18.

The robotics competition, is designed to encourage youths to pursue careers in math and science, and have attracted teams of teenagers from more than 150 nations. 

Competition organizers say they learned Tuesday night that the team’s mentor could not find the students. FIRST Global President Joe Sestak made the initial call to police, according to a statement issued Thursday. Two of the teens were seen crossing into Canada, D.C. police say. The members of the robotics team from the eastern African country of Burundi, who are 16, 17 and 18, disappeared Tuesday after they took part in the FIRST Global Challenge robotics competition. 

The Metropolitan Police Department has received reports that Audrey Mwamikazi, 17, and Don Ingabire, 16, were seen crossing into Canada, spokeswoman Aquita Brown said Thursday morning.

Police say they have no indication of foul play in their disappearance. No additional details were released immediately. The team’s mentor said they disappeared after the competition. He said he did not know where they went. The mentor told police the teens have one-year visas to stay in the U.S.