Photo taken on September 2, 2020 shows the US Capitol Building in Washington, D.C., the United States. Photo: Xinhua

US Capitol has been on lockdown on Friday afternoon after two police officers were reportedly injured as a car crashed into barriers surrounding the complex.

Capitol Police opened fire at the north barricade of the Capitol complex, law enforcement sources told ABC News.

The US Capitol Police (USCP) tweeted 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.

Capitol Police sent out an alert notifying those in the complex that they should remain indoors.

There was a heavy police response outside of the Capitol, including a helicopter landing on the premises.