One woman and two men "appeared to have suffered from separate medical emergencies, which resulted in their deaths," Washington DC's Metropolitan Police Department chief Robert Contee said.
"The gunshot wound victim … she is the one transported from the scene to an area hospital," the police chief added.
The violent protests also resulted in 14 injured police officers, with two of them currently in hospital.
The fatal gunshot victim has been identified as air force vet and Californian Trump supporter Ashli Babbitt, with her husband confirming the news with KUSI-TV.
BREAKING: Family confirms woman shot & killed at Capitol is Ashli Babbit. She owned a business in San Diego w/ her huband who did not come to DC. “I really dont know why she decided to do this,” her mother-in-law tells me. Police have not confirmed circumstances of shooting pic.twitter.com/OOYpNWpMLg
Just a day before her death, Babbitt took to Twitter to vow that "nothing will stop us".
"They can try and try and try but the storm is here and it is descending upon DC in less than 24 hours ... dark to light," she posted.
The chaos arose after MAGA protesters stormed the Capitol in an attempt to overthrow democracy in the dying days of Donald Trump's presidency this morning.
The outgoing President's supporters have not only taken to the streets, but have also breached the US Capitol building after breaking through barriers, withstanding tear gas and engaging in an armed standoff with police in a stunning refusal to accept Trump's election loss.