Local residents stand outside a shop with graffiti reading "leader of Muslims Mullah Mohammad Omar," on Sunday, May 8, 2011, in Pashin, 100 kilometers south of Quetta, Pakistan. (Arshad Butt/AP)

Afghanistan’s main intelligence agency said Monday it is investigating reports that Taliban leader Mohammad Omar and some of his top commanders have left their hideout near the Afghan-Pakistan border and cannot be located.

The reports led some Afghan media outlets to say that Omar might have been killed. But the Taliban staunchly denied that in a statement issued Monday.

“Claims and rumors were spread this morning by the Kabul stooge regime’s intelligence directorate, other officials and some media outlets that the esteemed Amir ul-Mumineen was martyred in Pakistan,” the Taliban statement about Omar said. “We strongly reject these false claims of the enemy.” The statement referred to Omar by a high Islamic title that translates as “commander of the faithful.”

A spokesman for Afghanistan’s intelligence bureau, Lutfullah Mashal, told reporters in Kabul that he “cannot confirm officially whether [Omar] is dead or alive.”

Mashal quoted unidentified “sources” on the Pakistani side of the border as saying Omar “disappeared from his location in the last four or five days.” He said Omar has been living in Quetta, the capital of Pakistan’s Baluchistan province, for 10 years.

“Our sources and senior Taliban commanders have confirmed that they have not been able to contact Mullah Omar,” Mashal said. “So far, we cannot confirm the death or killing of Mullah Omar officially, but we can confirm that he has ... disappeared from his hideout in Quetta of Baluchistan.” Quetta, a city of about 900,000 people, lies 124 miles southeast of Kandahar, the birthplace of the Afghan Taliban and long a stronghold of the Islamist radical movement in southern Afghanistan.

Omar, who is believed to be in his early 50s, was born into an impoverished Pashtun family near Kandahar and joined the fight against the Soviet invasion of Afghanistan in the 1980s. He lost an eye in battle from a shrapnel wound sometime in the 1980s and began studying and teaching in Islamic seminaries, or madrassahs, in Pakistan. It was during this period when he reportedly met Osama bin Laden, who went on to found the al-Qaeda terrorist network.

The Soviet Union withdrew its forces from Afghanistan in 1989, leaving behind a Soviet-backed government that fell three years later. In the ensuing chaos of civil war among the anti-Soviet mujaheddin factions, Omar began organizing madrassah students in an armed Islamist movement that became known as the Taliban.

By September 1996, the movement had captured Kabul, although the civil war continued in northern parts of the country against an alliance led largely by ethnic Tajiks. The Taliban formed a government called the Islamic Emirate of Afghanistan, with Omar as the de facto head of state. The movement imposed a harsh version of Islamic law on the country. It suppressed women, forced men to wear long beards, punished transgressors with stonings and amputations and destroyed the country’s renowned pre-Islamic Buddha statues at Bamiyan.

Omar mostly stayed away from Kabul, preferring to lead a reclusive existence in Kandahar, where he lived in a house reportedly built for him by bin Laden and shunned contact with most foreigners.

Omar remained close to bin Laden, however, allowing the al-Qaeda leader to set up training camps and safehouses and plot terrorist attacks against the United States, including the strikes of Sept. 11, 2001. In retaliation for those attacks, the United States launched a campaign of airstrikes against Taliban and al-Qaeda targets in Afghanistan and helped the Afghan forces known as the Northern Alliance drive the Taliban from Kabul in November 2001.

Omar fled Kandahar and went into hiding. Bin Laden escaped across the border into Pakistan, eventually establishing himself in a fortress-like house in the military garrison city of Abbottabad, about a two-hour drive north of the capital, Islamabad. There, U.S. commandos found and killed him in a raid early on May 2.

In a November 2001 interview with the BBC’s Pashto service, conducted through an intermediary, Omar declared as a goal “the destruction of America” and predicted that “this will happen within a short period of time.” He said a plan to destroy the United States was “being implement,” adding: “But it is a huge task, which is beyond the will and comprehension of human beings.”

Branigin reported from Washington.