Less than a week after a violent mob stormed the Capitol in a deadly security breach, the Secret Service expressed confidence Monday in a sprawling plan to secure the presidential inauguration, describing it as a “zero fail mission.”

Michael Plati, the agent leading the effort, vowed a “robust … presence” of law enforcement and National Guard, along with a layered network of fencing and vehicle checkpoints to repel potential threats.

Plati described last week’s security collapse as a “poignant reminder” of the consequences for any breakdown.

“We have a zero fail mission,” he said. “We feel we are prepared to address the challenges presented by that day.”

Though Plati did not address specific threats posed to the inauguration, the FBI warned authorities of the possibility of armed demonstrations on Inauguration Day, Jan. 20, in Washington and in state capitals in the run-up to the swearing-in of the new president, according to an official with knowledge of the matter. The official, who is not authorized to comment publicly, said the FBI’s guidance is based on intelligence gleaned from social media platforms where activists have called for a new round of clashes. 

Five people, including a U.S. Capitol Police officer, died as a result of last week’s violence when attackers, many of them armed and waving flags in support of President Donald Trump, rushed the Capitol where lawmakers were formally confirming Biden’s victory in November’s election.

More:US Capitol Police Officer Brian Sicknick is the fifth person to die from the protest

There will be 10,000 National Guard troops in Washington for the inauguration, Gen. Daniel Hokanson, chief of the National Guard Bureau, said Monday. They will provide security, logistics and communication. An additional 5,000 Guard troops could be called up if needed, he said.

The authorization for 15,000 Guard troops dwarfs the 340 Guardsmen requested by officials in the District of Columbia before the attack on the Capitol Jan. 6. Those troops were sought for traffic control and security at Metro mass transit stations.

At least 200 officers from the New York Police Department are also being dispatched to Washington to assist Jan. 20, an NYPD official said Monday.

The inauguration is one of the most daunting tasks for law enforcement authorities.

The clash at the Capitol offered a jarring image of vulnerability on the very grounds where President-elect Joe Biden and Vice President-elect Kamala Harris will be sworn in.

A cascade of security failures led to the resignations of top Capitol law enforcement officials, including U.S. Capitol Police Chief Steven Sund.

Much of the focus for the security collapse has been centered on the failure to place National Guard units at the ready before the demonstration.  

Sund said House and Senate security officials turned down his requests to put the National Guard on standby in the days before the deadly riot.

The chief, who resigned the day after the riot, told The Washington Post that the House and Senate sergeants at arms told him they were not comfortable with the “optics” of declaring an emergency days before the protest and suggested Sund should informally ask Guard officials to be on alert. The House and Senate officials also resigned.

Sund said he pleaded for help five more times as the riot unfolded. A crowd of several thousand quickly overran the Capitol Police contingent of 1,400 officers.

Plati said last week’s troubling scene has been incorporated in the overall security plan for the inauguration, referring to the events as “lessons learned” for authorities securing a signature demonstration of American democracy that typically draws a contingent of former presidents, their families, foreign dignitaries and representatives of much of the government.

The operation, designated as a National Special Security Event, is led by the Secret Service and includes Washington’s Metropolitan Police Department, the U.S. Park Police, U.S. Capitol Police and the Pentagon. Hundreds of police officers from across the country also are involved.

Despite lawmakers’ criticism of the Capitol Police response to the riot, Plati characterized the agency as an integral part of the inauguration plan. Monday, acting Homeland Security Secretary Chad Wolf met Secret Service officials to review the strategy.

Plati said “a very robust law enforcement presence” across the city will be augmented by fencing, barricades and other physical security features.

The prospect of a mass disturbance, Plati said, has always been part of the plan “to deal with protests that could become unlawful.”

Trump confirmed he won’t attend the inauguration after spending weeks since he lost the Nov. 3 election leveling unsubstantiated claims of voter fraud to try to overturn the results. He expressed support for last week’s demonstration and urged his supporters to march to the Capitol.

“One of the few things he and I’ve ever agreed on – him not showing up,” Biden said last week, referring to Trump’s decision not to attend.  Conversely, he said he would welcome Vice President Mike Pence’s attendance and would be “honored to have him there.”

Biden expressed confidence in the Secret Service and the inaugural security plan.