If confirmed, the drone strike in Pakistan's tribal belt, along the Afghan border, would be the first since President Obama announced sweeping changes to the drone program last week, including new limits on who would be targeted and more transparency in reporting such strikes. But that map for use of American power seemed to be some distance down the road on Wednesday, as American officials refused to confirm the strike or any details for hours after the news was being reported in Pakistan.
It also remained to be seen whether American officials would try to argue that Mr. Rehman posed a "continuing and imminent threat" to citizens of the United States – one of Mr. Obama's guiding criterion for future drone strikes. Mr. Rehman, who has long been thought to be the Pakistani Taliban's main operations leader, has a $5 million United States government bounty on his head, and is accused of organizing attacks on American troops across the border in Afghanistan.
Inside Pakistan, Mr. Rehman's death provoked a complex set of reactions. The Foreign Ministry quickly condemned the strike in a statement, while the incoming prime minister, Nawaz Sharif, who is due to take office next week, has vowed to restrict drone activity as part of a broader tightening to relations with the United States.
Some analysts and conservative leaders speculated that Mr. Rehman's death could make it harder for Pakistan to strike a peace deal with the Taliban, because Mr. Rehman was seen as less extreme than the movement's fugitive leader, Hakimullah Mehsud.
Against that, however, many other Pakistanis are unlikely to regret Mr. Rehman's death. As the Taliban's deputy leader, he orchestrated suicide bombings that have killed thousands of civilians and Pakistani military personnel over the past six years. Some American officials in Washington have even come to refer to strikes against such militant figures as "good-will kills," suggesting that some officials in Islamabad and Rawalpindi, the Pakistani military headquarters, would cheer them.
In many ways, Mr. Rehman embodies the metamorphosis of the Pakistani Taliban in the years after the 2001 terror attacks from a group of disgruntled Pakistani tribal militants into a destructive force nurtured by Al Qaeda and aiming its weapons – guns and rockets, but also teenage suicide bombers — inside Pakistan and beyond.
The Pakistani military says that several tens of thousands of civilians and soldiers have died since the Taliban insurgency fully erupted in 2007. In the past year, the Pakistani Taliban stared to kill polio vaccinators in the northwest – the latest casualty, a female health worker, died on Tuesday.
More recently, it sought to influence the recent May 11 election by targeting candidates of secular parties and their supporters, 130 of whom died in the final month of campaigning.
Two security officials, one speaking from the regional capital, Peshawar, said that Mr. Rehman was among five people killed when missiles fired from a drone struck a house outside Miram Shah, the main town in the tribal district of North Waziristan, at about 3 a.m. Wednesday.
A local resident, reached by phone, said that shortly after the strikes, three pickup trucks carrying fighters rushed to the site to retrieve bodies and look for wounded militants. Two Uzbek militants were also killed, Pakistani officials said.
A Taliban commander, speaking in a telephone interview on the condition of anonymity, confirmed that Mr. Rehman was among the dead. But the official Taliban spokesman said he had no such information. "I am neither denying nor confirming it," the spokesman, Ehsanullah Ehsan, said in a telephone interview.
The identity of those killed in drone strikes is notoriously difficult to confirm because the remote tribal areas are inaccessible to foreign and most local journalists. Previously Mr. Rehman's boss, Hakimullah Mehsud, was falsely reported to have died in a drone strike in 2010, only to emerge unscathed months later.
But the volume and variety of sources, official and militant, that reported the attack on Mr. Rehman suggested he had indeed been killed.
In his early 40s and from a mountainous district of South Waziristan, Mr. Rehman has grown in prominence over the past two years as the group's top leader, Mr. Mehsud, was hunted by American drones. In addition to that, the two men developed serious differences over the future direction of the insurgency, creating speculation with militant circles of a serious rift within the group.
While Mr. Mehsud adhered to the hard-line Salafist strain of Islam, and aligned himself closely with Al Qaeda fighters sheltering in Waziristan, Mr. Rehman subscribed to the relatively moderate Deobandi school of thought, and was linked to the Haqqani Network, which concentrates on attacks across the border in Afghanistan.
Inside the Taliban, Mr. Rehman was seen as a conciliatory figure, who helped mediate disputes with other militant factions, and who was opposed to the indiscriminate attacks on civilians that have become the Taliban hallmark in recent years.
"Wali was always at the forefront whenever a dispute emerged with Hafiz Gul Bahadur, the Haqqanis or Mullah Nazeer," said one Taliban commander, referring to the leaders of Taliban-linked militant factions in Waziristan, speaking on condition of diplomacy.
Inside the movement, the militant added, "his weapon was diplomacy."
Mr. Rehman also had ties with several religious parties, some of which had offered to mediate with the Taliban. Mualana Syed Yusuf Shah, the deputy leader of one of those parties, said his death would make it harder to negotiate peace.
"Everything has been overturned," he said. "Now the Taliban will avenge his killing, resulting in more bloodshed and violence across the country," Mr. Shah said in an interview.
Even as Mr. Obama said he was tightening the standards by which drone strikes would be allowed, administration officials have said—anonymously – that for months to come the C.I.A. will continue to carry out drone strikes in Pakistan under the more permissive standards used in the past.
The Pakistani Taliban have long been in the American government's sights, however, and the apparent strike on Wednesday would mark the second successful American action against a major Pakistani Taliban leader if it is confirmed. In August 2008, a C.I.A.-controlled Predator drone fired missiles that killed the previous leader of the Pakistani Taliban, Baitullah Mehsud.
In addition to attacking American soldiers in Afghanistan, the group helped train Faisal Shahzad, the naturalized American citizen who tried to detonate a car bomb in Time Square in May 2010. American officials also accuse the Pakistani Taliban of carrying out a multipronged attack on the United States consulate in Peshawar in April 2010 that killed six Pakistanis and wounded 20.
The group is also accused of organizing the killing of seven Americans at a C.I.A. outpost at Forward Operating Base Chapman, in the eastern Afghan province of Khost, in 2009. Hakimullah Mehsud publicly reveled in that attack, claiming he had personally trained and supported the bomber, and the American government says Mr. Rehman played a planning role in that attack as well.
In a statement issued Wednesday afternoon, Pakistan's Ministry of Foreign Affairs expressed "serious concerns" over the drone strike. Such attacks "violate the principles of national sovereignty, territorial integrity and international law," the statement said.
The C.I.A. has carried out about 360 drone strikes in Pakistan since 2004, but the rate of attack has dropped sharply this year amid fierce scrutiny of the program in the United States. So far this year there have been about 13 strikes.
One senior United States official said officials at the C.I.A.'s Counter-Terrorism Center, which runs the drones program, had fiercely opposed the most significant changes during the administration's two-year long internal debate to reshape drones policy.
"Of course, there are people at the C.T.C. who are not pleased with this, but the leadership understands the change," said the official, who spoke on condition of anonymity to discuss internal administration discussions. "Change makes people nervous."
Reporting was contributed by Mark Mazzetti and Eric Schmitt from Washington, Ismail Khan from Peshawar, Pakistan, and Ihsanullah Tipu Mehsud from Islamabad.
