Police open fire after vehicle tries to break barrier at US Capitol

After reports that someone hit two U.S. Capitol Police officers with a car, Capitol Police opened fire at the north barricade of the Capitol complex, law enforcement sources tell ABC News. Two officers are said to be injured, one critically, the sources said. The U.S. Capitol Police (USCP) said in a tweet shortly before 1:30 p.m. ET they are "responding to the North Barricade vehicle access point along Independence Avenue for reports someone rammed a vehicle into two USCP officers." A suspect is in custody, the police said in the tweet, and both officers and the suspect were transported to the hospital. The Capitol is on lockdown due to this situation. Staffers on the Hill were sent a message from U.S. Capitol Police around 1:20 p.m. ET saying "due to an external security threat" that "no entry or exit is permitted." The message said people could move around inside the building, "but stay away from exterior windows and doors. If you are outside, seek cover." It is still unknown if this was an intentional attack, a briefed federal official told ABC News, and investigators are actively trying to figure that out. There was no heightened threat posture at the Capitol before this occurred on Friday.