WASHINGTON (AP) — Law enforcement was on high alert Thursday around the U.S. Capitol after authorities said intelligence had uncovered a “possible plot” by a militia group to storm the iconic building again. The alert came two months after Donald Trump supporters smashed through windows and doors to try to stop Congress from certifying now-President Joe Biden's victory.

The threat appeared to be connected to a far-right conspiracy theory, mainly promoted by supporters of QAnon, that former President Trump would rise again to power on March 4 and that thousands would come to Washington to try to remove Democrats from office. March 4 was the original presidential inauguration day until 1933, when it was moved to Jan. 20.

There were no signs of disturbance Thursday at the heavily secured building, with Capitol Police and National Guardsmen on duty and a large fence around the perimeter that was put in place after the Jan. 6 riot. The Pentagon is reviewing a request to extend the Guard deployment 60 days beyond its current expiration date of March 12.

Online chatter identified by authorities included discussions among members of the Three Percenters, an anti-government militia group, concerning possible plots against the Capitol on Thursday, according to two law enforcement officials who were not authorized to speak publicly and spoke on condition of anonymity. Members of the Three Percenters were among the extremists who stormed the Capitol on Jan. 6.

The threat came as the Capitol police and other law enforcement agencies were taking criticism from Congress in contentious hearings this week on their handling of the Jan. 6 riot. Police were ill-prepared for the mass of Trump supporters, some in tactical gear and armed, and it took hours for National Guard reinforcements to come. By then, rioters had broken into the building and they roamed the halls for hours, stalling Congress' certification effort temporarily and sending lawmakers into hiding.

Lawmakers, congressional staffers and law enforcement officials are still on edge after the attack on Jan. 6, even as security around the Capitol remains at an unprecedented level.

The U.S. House wrapped up its work for the week Wednesday night, but the U.S. Senate still had a busy day scheduled for Thursday with votes into the evening. Police beefed up their presence in and around the Capitol. About 5,200 National Guard members remain in D.C., the remainder of the roughly 26,000 who were brought in for President Biden's inauguration in January, which went off with no problems.

Rep. Michael McCaul, R-Texas, the former chairman of the House Homeland Security Committee and among those briefed about the new threat, said lawmakers were braced.

“I think we’ll see some violence here,” he said in an interview.

But unlike on Jan. 6, the Capitol is now fortified against intrusions. “We have the razor wire, we have the National Guard. We didn’t have that January 6. So I feel very confident in the security," he said.

Initially it seemed as though the online chatter did not rise to the level of serious concern; an advisory sent earlier this week to members of Congress by Timothy Blodgett, the acting House sergeant-at-arms, said the Capitol Police had “no indication that groups will travel to Washington, D.C., to protest or commit acts of violence.”

But that advisory was updated in a note to lawmakers Wednesday morning. Blodgett wrote that the Capitol Police had received “new and concerning information and intelligence indicating additional interest in the Capitol for the dates of March 4th – 6th by a militia group.”

Acting Capitol Police Chief Yogananda Pittman said during House testimony Wednesday that her investigators had collected “some concerning intelligence,” but declined to provide any details publicly, saying that it was “law enforcement sensitive” and that she would provide a private briefing for the subcommittee members.

Meanwhile, federal agents found no significant increases in the number of hotel rooms being rented in Washington, or in flights to the area, car rental reservations or buses being chartered, a person familiar with the matter told The Associated Press. The person could not publicly discuss details of the security planning and spoke on the condition of anonymity.

The FBI and Department of Homeland Security also sent a joint intelligence bulletin to local law enforcement officials Tuesday that said a group of militia extremists had discussed trying to take control of the Capitol on March 4 and encouraging thousands of people to come to D.C. to try to remove Democrats from power.

But there has been a noticeable decline in online activity on some social media platforms surrounding efforts on March 4, and there was already considerably less online chatter than during the lead-up to Jan. 6, a day that Trump repeatedly had promoted for a his rally and encouraged thousands to come to the nation's capital.

Also, thousands of accounts that promoted the Jan. 6 event that led to a violent storming of the U.S. Capitol have since been suspended by major tech companies like Facebook and Twitter, making it far more difficult for groups to organize a repeat of the mass gathering.

So far, about 300 people have been charged with federal crimes for their roles in the riot. Five people, including a Capitol Police officer, died.

Since his defeat, Trump has been promoting lies that the election was stolen from him through mass voter fraud, even though such claims have been rejected by judges, Republican state officials and Trump’s own administration. He was impeached by the House after the Jan. 6 riot on a c harge of incitement of insurrection but was acquitted by the Senate.

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Associated Press writers Nomaan Merchant in Houston; Alan Fram, Mary Clare Jalonick, Colleen Long, and Lisa Mascaro in Washington, and Amanda Seitz in Chicago contributed to this report.