The US Capitol was in lockdown on Thursday after gunshots were fired outside the building, injuring several people including a law enforcement officer, a Senate aide and a Capitol police officer said.

The US House of Representatives and Senate were in session when the gunshots were heard. The US government was partially shut down this week when lawmakers failed to agree on a budget.

Police called in a Medevac helicopter, a Senate aide and a US Capitol policeman said. The Senate chamber was locked with staff inside. Senate leaders were locked in their offices. The shots were fired near the Hart Senate Office Building at 2nd St and Constitution Avenue Northeast, only a few blocks from the US Supreme Court.

Related:

Shutdown in 3rd day with Obama, Hill at impasse