The president will meet with Afghan President Hamid Karzai in Kabul, after a flight that was kept secret by the White House until Mr. Obama arrived there. The two leaders are to sign an agreement cementing the U.S. role in the country after the war ends in 2014.
Mr. Obama will give a televised address to the U.S. around 7:30 p.m. Eastern time.
At least 33 U.S. service members were killed in Afghanistan in April, making it the deadliest month this year.
The timing of the trip, on the anniversary of bin Laden’s slaying by a Navy SEAL team in Pakistan, was certain to raise more complaints that Mr. Obama is using last year’s raid for political gain. His campaign has criticized presumptive Republican nominee Mitt Romney for lacking the resolve necessary to have approved the bin Laden mission.
Just on Monday, Mr. Obama dismissed charges that he or his campaign team were exploiting the anniversary.
“I hardly think you’ve seen any excessive celebration taking place here,” Mr. Obama said.
“We finally brought to justice the man behind the 9/11 attacks and so many acts of violence,” Mrs. Obama said to applause.
Former Defense Secretary Donald Rumsfeld wrote on his Twitter account, “The special operators who have every right to ‘spike the football’ are too professional to do so. The White House might follow their lead.”
Mr. Romney has said Mr. Obama has every right to take credit for bin Laden’s demise. But the GOP candidate said it was “very disappointing for the president to try to make this a political item” by claiming Mr. Romney wouldn’t have ordered the raid.
“Of course I would have,” Mr. Romney said.
The trip to Afghanistan was conducted in secrecy and with some evasion. Foreign news outlets began reporting Mr. Obama’s arrival in the country Tuesday morning. A White House spokesman told The Washington Times around 11:15 a.m. Tuesday that Mr. Obama was not in Afghanistan. But when asked whether the president was in transit to or from the region, officials would not answer the question.
The New York Post, which posted a brief story on the president’s trip Tuesday morning citing foreign news services, later removed the item from its website. Pool reporters traveling with the president, who left Washington shortly after midnight Monday, were embargoed from reporting on the trip until around 3 p.m. Tuesday.
There is precedent for presidents traveling in secrecy to war zones. President George W. Bush made a covert trip to Iraq on Thanksgiving 2003, when Americans were told he was at his ranch eating turkey and watching football.
President Franklin D. Roosevelt used a body double to sneak away for a meeting with British Prime Minister Winston Churchill during World War II. President Lyndon B. Johnson quietly paid a visit to U.S. troops in Vietnam.
There have even been some evasive trips during peace time. With concerns for his safety, President Clinton flew into Pakistan in March 2000 by switching planes during his departure from India and taking an unmarked plane to Islamabad.
The U.S. military gave its semi-annual report to Congress Tuesday on the war in Afghanistan, saying Mr. Obama’s surge of 33,000 extra troops had weakened the Taliban but major threats remain from an insurgency, government corruption and selective cooperation from Pakistan.
The Pentagon said insurgent attacks decreased in 2011 for the first time in five years, although violence rose around the Taliban’s southern stronghold of Kandahar.
— Researcher John Sopko contributed to this report.