A District man was sentenced Wednesday to 20 months in prison for making bomb threats against Amtrak, U.S. Attorneys announced.

Michael Jerome Dennis, 27, made two separate bomb threats against the railroad company while working as a contractor at a site near the Amtrak bridge on New York Avenue NE, according to authorities.

Dennis admitted in May to making phone calls to Amtrak's National Communications Center on Nov. 30, 2011 and Jan. 19, 2012 that forced officials to delay trains while police searched the bridge and surrounding areas for explosives.

He was also sentenced to five years of supervised release after his prison term, must complete 200 hours of community service and undergo counseling.

Dennis must also pay $5,002 in restitution to Amtrak, which had to delay trains for more than 1,000 customers.