ISLAMABAD — An al-Qaida leader sought in the 2008 Mumbai siege and rumored to be a longshot choice to succeed Osama bin Laden was believed killed in a U.S. drone attack as he met with other militants in an apple orchard in Pakistan, an intelligence official said Saturday. If confirmed, it would be another blow against the terror organization a month after the slaying of its leader.

The purported death of Ilyas Kashmiri — who also was accused of killing many Pakistanis — could help soothe US-Pakistan ties that nearly unraveled after the May 2 bin Laden raid. While it was unclear how Kashmiri was tracked, his name was on a list of militants that both countries recently agreed to jointly target as part of measures to restore trust, officials have said.

It also would be a major victory for U.S. intelligence, particularly the controversial CIA-run drone program, which began in 2005 but has been increasingly criticized by the Pakistanis amid rising anti-American sentiment in the country.

Senior U.S. officials in Washington, Islamabad and the Afghan capital, Kabul, said they could not confirm that Kashmiri was killed. Other Pakistani officials also said they couldn’t confirm it.

Described by American officials as al-Qaida’s military operations chief in Pakistan, the 47-year-old Pakistani was one of five most-wanted militant leaders in the country, accused of a string of bloody attacks in Pakistan and India as well as aiding plots in the West. He also has been named a defendant in an American court over a planned attack on a Danish newspaper that published cartoons depicting the Prophet Muhammad in 2005.

Washington had offered a $5 million reward for information leading to his location.

One Pakistani intelligence officer said Kashmiri was believed killed along with eight other militants in a drone strike Friday close to Wana town in South Waziristan, not far from the Afghan border. A senior Pakistani security official said there “were strong indications” of his death.

All the officials spoke on condition of anonymity because of department policy and the sensitivity of the subject.

Verifying who has been killed in the drone strikes is difficult, with DNA samples or photographic evidence typically needed. Initial reports have turned out to be wrong in the past, including one in September 2009 that said Kashmiri had been killed. Sometimes they are never formally denied or confirmed in Pakistan or in the United States.

A fax purportedly sent by the militant group he was heading — Harakat-ul-Jihad al-Islami’s feared “313 Brigade” — confirmed Kashmiri was “martyred” in Friday’s 11:15 p.m. strike. It was sent to journalists in Peshawar, and its authenticity could not be independently confirmed. The group, which has not previously communicated with the media, promised revenge against America in the handwritten statement on a white page bearing its name of the group.

Soon after the attack, local intelligence officials said the slain men were in a large compound. The intelligence officer said Saturday that the militants were meeting in an apple orchard near the house when the missiles hit.

Kashmiri fought with jihadi fighters in Afghanistan and in Indian-held Kashmir in the 1990s, allegedly with the support of the Pakistani state, and was said to have lost a finger and been blinded in one eye during those conflicts. He reportedly once served in the Pakistani army, but he denied that in an interview in 2009. Like other top al-Qaida and allied militants, he was believed to be living in the tribal regions close to the Afghan border in recent years.

Indian officials have alleged Kashmiri was involved in the 2008 siege of a hotel and other targets in the Indian city of Mumbai that killed more than 160 people.

In an ongoing terror trial in Chicago, an admitted American-Pakistani militant has testified that Kashmiri helped plan the Mumbai siege and wanted to attack U.S. defense contractor Lockheed Martin. Kashmiri had been angry over U.S. drone attacks inside Pakistan and wanted to target the company, according to David Coleman Headley.

Headley, who pleaded guilty to laying the groundwork for the Mumbai attacks, also testified during the trial of his longtime friend Chicago businessman Tahawwur Rana that he worked with Kashmiri to plot the attack against the Danish newspaper. Headley said he traveled to Copenhagen to conduct surveillance. The attack was never carried out and Kashmiri was charged in absentia along with several others in the case.

Kashmiri has most recently been linked to last month’s 18-hour assault on a naval base in Karachi. He is also accused of masterminding several raids on Pakistan police and intelligence buildings in 2009, as well as a failed assassination attempt against then-President Pervez Musharraf in 2003.

Pakistani leaders did not immediately comment on Friday’s attack, but Kashmiri’s alleged involvement in attacks on Pakistanis was likely to mute the public reaction.

The U.S Department of State says he organized a 2006 suicide bombing against the U.S. consulate in Karachi that killed an American diplomat and three other people. In early 2009, it said Kashmiri operated a militant training center in Miram Shah in North Waziristan.

Considered to be one of al-Qaida’s most accomplished terrorists, he had been mentioned by security analysts as a contender for replacing bin Laden as head of the group, though many thought the fact that he was not an Arab dampened his chances.

Ties between Washington and America have deteriorated since the bin Laden raid. Pakistanis viewed the unilateral operation as a violation of sovereignty, while bin Laden’s location in an army town close to the capital added to long-standing suspicion in Washington that elements of Pakistan’s security forces were protecting him.

With fresh leverage, American officials made it clear they expected Pakistan to boost efforts to locate other al-Qaida leaders in the country. U.S. Secretary of State Hillary Rodham Clinton said in Islamabad two weeks ago she expected Pakistan to “take decisive steps” in the days ahead.

The U.S. drone strikes have been controversial since they picked up pace in 2008, with about 30 reported so far this year.

Pakistani army officers and politicians publicly protest them, too weak to admit to working with the ever unpopular America in targeting fellow Pakistanis, but the country’s intelligence agencies have been known to provide targeting information.

Opposition to the strikes grew this year after a CIA contractor shot and killed two Pakistanis in the street, triggering ever more intense anti-American anger. After the bin Laden raid, the parliament issued a declaration calling for the attacks to end.

The United States does not acknowledge the CIA-run program, though its officials have confirmed the death of high-value targets before, including the head of the Pakistani Taliban, Baitullah Mehsud, in 2009 — a strike welcomed by many Pakistan officials because he too was a sworn enemy of the country.