WASHINGTON (BLOOMBERG) - New York Representative Alexandria Ocasio-Cortez said she thought she was going to die when supporters of President Donald Trump stormed the Capitol last week and she feared some law enforcement officers and other members of Congress might be encouraging the mob.

"I had a pretty traumatising event happen to me, and I do not know if I can even disclose the full details of that event, due to security concerns, but I can tell you that I had a very close encounter where I thought I was going to die," Ms Ocasio-Cortez said an hour-long Instagram Live late on Tuesday (Jan 12).

"I did not know if I was going to make it to the end of that day alive - and not just in a general sense, but also in a very, very specific sense."

The second-term Democrat, who is one of the most recognisable members of Congress and often vilified by right-wing media, said she felt unsafe when she was brought to a secure room with other lawmakers whom she suspected "would create opportunities to allow me to be hurt".

"Many of us nearly and narrowly escaped death," she said.

"There was a sense that something was wrong from the inside."

Several Democrats have suggested that the attackers on Jan 6 had help from people who knew the maze-like halls of the Capitol building.

Although one Capitol Police officer died after confronting rioters and more than 50 officers were injured, videos from the event showed other officers chatting and interacting with rioters wearing Trump paraphernalia.

"There were those acts of heroism, but next to that there was also acts of betrayal," Ms Ocasio-Cortez said.

"And to run in the Capitol, in our nation's Capitol, and not know if an officer is there to help you or to harm you is also quite traumatising."

Representative Mikie Sherrill, a New Jersey Democrat, said she witnessed lawmakers giving what she believes to be "reconnaissance" tours the day earlier.

She didn't share any evidence to support that claim.

Speaking in a video statement posted to Facebook, Ms Sherrill, a former Navy pilot, said she saw unspecified members "who had groups coming through the Capitol that I saw on Jan 5, a reconnaissance for the next day".

Separately, she recalled seeking safety on the day of the attack, worried that some members of Congress were deliberately "following us as we were taking everyone to the secure location".

Ms Sherrill alleged that some of her congressional colleagues incited the mob and tried to help Mr Trump overturn the results of the election.

She said she plans to "see they are held accountable, and if necessary, ensure that they don't serve in Congress."