Two gunpoint robberies have been reported within the past two weeks in the Georgetown area near the entrance to the Capital Crescent Trail, a scenic recreational site and rail trail that runs from the District to Silver Spring.

Though stress and other factors sometimes impair the accuracy of descriptions given by crime victims, U.S. Park Police said Friday that they were told in both cases that the robbers had a “machine gun.”

Both robberies, police said, occurred near the Aqueduct Bridge abutment, an architectural remnant along the Potomac River feet from the Key Bridge and Whitehurst Freeway.

The first robbery occurred Jan. 6 shortly after 8 p.m., police said.

Police said one of three teenage robbers had the “machine gun” and another had a handgun.

The second holdup was reported Wednesday about 3 p.m., involving two robbers with similar descriptions and carrying the same weapons as in the earlier robbery, police said. No injuries were reported in either incident.

In the first robbery, the park police said victims described all three robbers as black, male, and from 16 to 18 years old.

One was about 5 feet 11, husky and masked; a second was about 5 feet 9, and thin, and the third was about 5 feet 6, with dark clothing, the police said.

In the second robbery, the two robbers were said to be black, male and about 19 or 20.

One was about six feet, dark, with a medium build, shoulder length dreadlocks, and a mask.

According to police, the other was said to be about 5 feet 9, dark, thin with short hair shaved on the sides. He wore a red and black hat, a black Adidas jacket, black shoes with red soles, the police said.