WASHINGTON - A man with an apparent obsession with President Barack Obama has been arrested in Pennsylvania after the Secret Service discovered two bullets struck the White House while the president was away, authorities said Wednesday.

One bullet smashed into a window of the living quarters of the executive mansion but was stopped by ballistic glass.

The arrest of Oscar Ramiro Ortega-Hernandez, 21, came days after reports of shots fired on Friday night near the White House while Obama and his wife Michelle were on a trip to California and Hawaii. The president has since traveled on to Australia, second stop on a nine-day Asia-Pacific tour, and the White House had no comment on the unfolding events.

The U.S. Secret Service said it discovered Tuesday that the two bullets hit the White House. U.S. Park Police had earlier linked Ortega, a 21-year-old man from Idaho Falls, Idaho, to the reports of gunfire.

A U.S. Park Police crime bulletin issued before Ortega's arrest said he is known to have mental health issues, adding "Ortega should be considered unstable with violent tendencies."

Authorities are investigating his mental health and say there are indications he believed his attack on the White House was part of a personal mission from God, according to a law enforcement official. There are also indications the man had become obsessed with Obama and the White House, according to two officials, who spoke on the condition of anonymity because the investigation is ongoing.

Authorities said the bullets discovered Tuesday by the Secret Service have not been conclusively connected with the reports of gunfire near the White House on Friday night. On Friday, authorities found an abandoned vehicle with an assault rifle inside.

Ortega, 21, was arrested Wednesday afternoon at a hotel near Indiana, Pa., some 55 miles east of Pittsburgh, the Secret Service said. He was in Pennsylvania State Police custody. A tip from someone who saw and identified Ortega led to his arrest, Secret Service spokesman George Ogilvie said.

Ortega did not resist arrest, said Pennsylvania State Trooper Lt. Brad Shields. State troopers said Ortega had visited the hotel in recent days, and investigators believed he was back in the area Wednesday. The Secret Service passed out photographs, and a desk clerk recognized his picture and stalled him while notifying police.

Ortega's first court appearance is scheduled Thursday afternoon in Pittsburgh, according to the staff of U.S. Magistrate Judge Cynthia Reed Eddy.

Ortega was reported missing Oct. 31 by his family. On Friday morning, he was stopped by police in the Washington suburb of Arlington, Va., while investigating a report of a suspicious person. Police took photos of him but didn't have any reason to arrest him, Arlington police Lt. Joe Kantor said.

A message left for Ortega's mother Wednesday at an Idaho Falls restaurant where she works was not returned. Phone listings for family members in Idaho were disconnected.

Ortega has an arrest record in three states but has not been linked to any radical organizations, U.S. Park Police have said. Police searched the Occupy D.C. encampment Monday after callers said they had seen a man matching Ortega's description, but the search turned up nothing.

Witnesses on Friday reported hearing shots and seeing two speeding vehicles on Constitution Avenue near the White House. Authorities said they found an abandoned car, with the assault rifle inside, near the Theodore Roosevelt Bridge, which crosses the Potomac River to Virginia.

The bullet that hit the White House window was stopped by ballistic glass. The Secret Service didn't disclose the location of the second bullet, saying only that it "was found on the exterior of the White House."

Obama and the first lady had traveled without daughters Malia and Sasha on Friday to San Diego en route to Hawaii for a summit, prior to flying to Australia. The White House had no immediate comment on the shooting or on who may have been home at the time.

On Wednesday, officials took photographs of a window on the executive mansion's south face. The window is in front of the so-called Yellow Oval Room, according to the White House website. That room is in the middle of the family's living quarters on the floor that includes the president's bedroom and the Lincoln Bedroom.

In 2010, there were a series of pre-dawn shootings at military buildings in the Washington area, including the Pentagon and the National Museum of the Marine Corps. Police charged a Marine Corps reservist with those shootings earlier this year. The suspect, Yonathan Melaku of Alexandria, Va., remains in custody.

In the last shooting at the White House in October 1994, a Colorado man sprayed the mansion with at least 27 semiautomatic rifle bullets from Pennsylvania Avenue in an attempt to assassinate then-President Bill Clinton, who was home at the time. Bystanders subdued the suspect, and no one was injured. Francisco Martin Duran was convicted and sentenced to 40 years in prison for that shooting.

The next year, Pennsylvania Avenue was closed to traffic to bolster security.

Associated Press writers Jessie Bonner in Boise, Idaho, Joe Mandak in Pittsburgh, Kevin Begos in Indiana, Pa., Matt Apuzzo in Washington and AP photographer Haraz Ghanbari in Washington contributed to this report.