Three rockets were fired on Friday at a building leased as the site of a future U.S. consulate in the western Afghan city of Herat, police said, Reuters reported.
One rocket hit the former hotel, shattering windows, and two others landed nearby, said Rahmatullah Sediqi, the deputy provincial police chief in Herat.
No one was hurt, but police later fired in the air to disperse crowds, he said.
The U.S. government acquired the building in 2009 for a consulate in the city, one of at least two it plans to open outside the capital Kabul to boost its diplomatic presence.
No diplomats have yet been stationed at the site but Washington plans to open the consulate this year after renovating the building.
Herat, near the Iranian border, is a comparatively prosperous city where there has been little violence, although militants operate in surrounding rural districts.
U.S. embassy spokeswoman Caitlin Hayden said the embassy had heard reports of an attack on the building and was seeking confirmation from the Afghan authorities.
Asked if an attack could prompt the United States to review plans to house a mission at the site, she said: "Security is paramount for the embassy and we are continuously reviewing our security posture."