WASHINGTON -- The Secret Service chief has stepped-up security outside the White House after a man with a knife who jumped the fence made it into the presidential residence before being apprehended, officials said Saturday.

President Barack Obama insisted he still has confidence in the beleaguered agency's ability to protect him and his family.

Secret Service Director Julia Pierson ordered enhanced officer patrols and surveillance along the North Fence of the compound just after the incident on Friday evening, which triggered a rare evacuation of the White House as well as renewed scrutiny of the Secret Service. The agency said Pierson had also ordered a comprehensive review of what happened.

"The president has full confidence in the Secret Service and is grateful to the men and women who day in and day out protect himself, his family and the White House," said White House spokesman Frank Benenati. He said the White House expected Pierson's review to be conducted "with the same professionalism and commitment to duty that we and the American people expect from the U.S. Secret Service."

The presidential vote of confidence came as the storied agency sought to dispel growing concerns about security at the White House, one of the most heavily protected buildings in the world. Another man was arrested Saturday outside the White House in an unrelated event.

President Barack Obama and his daughters had just left the White House by helicopter on Friday evening when the Secret Service says 42-year-old Omar J. Gonzalez scaled the fence, darting across the lawn and through the unlocked North Portico doors before officers finally tackled him.

"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," the agency said in a statement. "Although last night the officers showed tremendous restraint and discipline in dealing with this subject, the location of Gonzalez's arrest is not acceptable."

The Secret Service's Office of Professional Responsibility was carrying out the review, which started Friday with interviews and a physical site assessment and will include a review of all of the security and operational policies, officials said.

Officials had originally said that Gonzalez appeared unarmed as he sprinted across the lawn -- potentially one reason agents didn't shoot him or release their service dogs to detain him. But Gonzalez had a small folding knife with a 3 1/2-inch serrated blade at the time of the arrest and faces a weapons charge, according to a criminal complaint issued late Friday.

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."

Gonzalez, of Copperas Cove, Texas, was transported to a nearby hospital after his arrest for evaluation. He was expected to appear in federal court Monday to face charges of unlawfully entering a restricted building or grounds while carrying a deadly or dangerous weapon.

Less than 24 hours after Gonzalez' arrest, a second man was apprehended after he drove up to a White House gate and refused to leave, the Secret Service said, prompting bomb technicians in full gear to search the vehicle as agents shut down nearby streets.

There were no indications the two events were connected. Yet the pair of incidents in short succession only intensified the scrutiny of the Secret Service, which is still struggling to rehabilitate its image following a series of allegations of misconduct by agents in recent years, including agents on Obama's detail.

"Unfortunately, they are failing to do their job," said Rep. Jason Chaffetz, chairman of the House subpanel on national security oversight, told the AP. "These are good men and women, but the Secret Service leadership has a lot of questions to answer."

"Was the door open?" he added incredulously.

On a quiet cul-de-sac about an hour's drive from Waco, Texas, where Gonzalez was last believed to have lived according to records, former neighbours said he moved out roughly two years ago. Sgt. 1st Class David Haslach, who lives two doors down from Gonzalez's former home, said Gonzalez had been in the U.S. military and told Haslach he had received a medical discharge.

He and another former neighbour, Elke Warner, both recalled him seeming paranoid in the months before he left town.

"At the end, he got so weird. He had motion detector lights put in," Warner said. She added that she last saw Gonzalez about a year and a half ago at a nearby camp site, where he was apparently living with his two dogs.

Attempts to reach Gonzalez or his relatives by phone were unsuccessful.

The Secret Service has struggled in recent years to strike the appropriate balance between ensuring the first family's security and preserving the public's access to the White House grounds. Once open to vehicles, the stretch of Pennsylvania Avenue in front of the White House was confined to pedestrians after the 1995 bombing of the federal building in Oklahoma City, but officials have been reluctant to restrict access to the area further.