Jim Michaels

USA TODAY

The U.S. Secret Service said it beefed up security Saturday around the White House after a man armed with a knife was able to scramble over the White House fence, dash across the expansive lawn and enter the massive front doors of the residence before agents nabbed him.

The first family was not at the residence when the incident occurred at about 7:20 p.m. Friday. The suspect, Omar Gonzalez, 42, of Copperas Cove, Texas, appeared to be unarmed at the time of the incident. However, the Associated Press reported that Gonzalez was carrying a small folding knife with a 3 ½-inch serrated blade, according to a criminal complaint filed late Friday night.

The latest breach of security has brought increased scrutiny to the agency. The Secret Service said the review of the incident will include an examination of how officers responded.

Secret Service Director Julia Pierson has ordered enhanced officer patrols and surveillance along the North Fence of the White House. The measures went into effect late Friday evening after the incident, according to the Secret Service.

"Every day the Secret Service is challenged to ensure security at the White House complex while still allowing public accessibility to a national historical site," according to a Secret Service statement issued Saturday evening. "Although last night the officers showed tremendous restraint and discipline in dealing with this subject, the location of Gonzalez's arrest is not acceptable."

Rep. Jason Chaffetz, R-Utah, who chairs the House of Representatives' subpanel on national security oversight, called it "totally unacceptable."

"Unfortunately, they are failing to do their job," Chaffetz said.

Intruders have made it over the fence before, but it is rare for someone to get across the lawn to the house before being stopped.

"This situation was a little different than other incidents we have at the White House," Secret Service spokesman Ed Donovan said. "There will be a thorough investigation into the incident."

Gonzalez was tackled just inside the doors of the North Portico, the columned entrance facing Pennsylvania Avenue.

He was charged with unlawful entry into the White House complex and transported to a nearby hospital complaining of chest pain.

According to a criminal complaint, when Gonzalez was apprehended he told Secret Service agents he was "concerned that the atmosphere was collapsing" and needed to contact the president "so he could get word out to the people."

Only minutes before the breach, Obama had boarded his helicopter on the South Lawn with his daughters and one of their friends, who was joining the Obamas for a weekend getaway to Camp David, the presidential retreat in Maryland. First lady Michelle Obama had traveled separately to Camp David and was not at home.

Less than 24 hours later, Kevin Carr, 19, of Shamong, N.J., showed up at one of the White House gates on foot, then showed up in his a car at another gate and pulled into the vehicle screening area. He refused to leave and was arrested for unlawful entry.

He did not breach security, Donovan said. He said such incidents happen frequently.

The Secret Service, which once enjoyed a sterling reputation as an elite force dedicated to protecting the president, has come under scrutiny in recent years.

In 2012, 13 Secret Service agents and officers were implicated in a prostitution scandal during preparations for Obama's trip to Cartagena, Colombia.

The next year, two officers were removed from the president's detail after another alleged incident of sexually-related misconduct. In March, an agent was found drunk by staff at a Dutch hotel the day before Obama was set to arrive in the Netherlands.

Contributing: The Associated Press