Pakistani civil society activists shout slogans during a demonstration in Multan on Monday against a U.S. drone strike in Pakistan's southwestern province of Balochistan. (Ss Mirza/AFP/Getty Images)

For years, Afghanistan’s military and political leaders have been urging the Obama administration to go after Taliban chiefs who can kill U.S. and Afghan troops one day and then eat in restaurants in southwestern Pakistan a day later. And for years, President Obama has apparently resisted that call, mindful of the United States’ complicated relationship with Pakistan.

Despite their shock five years ago when Obama sent the U.S. military into Pakistan to kill Osama bin Laden, Pakistani leaders believed they were largely sheltered from U.S. drones and warplanes. There was an agreement — a red line, as Pakistani leaders refer to it — that restricted U.S. drone strikes to Pakistan’s lawless tribal belt in the northwestern part of the country, they said.

But over the weekend, Obama again pulled the trigger, ordering the strike that killed Taliban leader Akhtar Mohammad Mansour in Baluchistan, far from the tribal belt. Now, some Pakistani leaders are rattled, saying they fear the United States is gearing up to bring the war in Afghanistan closer to Pakistan’s home front.

“It was the first drone strike in Baluchistan, and no doubt it was the crossing of the red line by the United States,” said Khalid Hussain Magsi, who represents that area in Parliament. “It’s a clear message that the U.S. can do such strikes wherever they feel is required.”

On Monday, while confirming the death of Mansour, the White House did little to soothe the undercurrent of anxiety.

“We will continue taking action against extremist networks that target the United States,” the White House said in a statement. “We will work on shared objectives with Pakistan, where terrorists that threaten all our nations must be denied safe haven.”

U.S. officials characterized the strike as an isolated operation. Mansour was “singularly opposed to peace in Afghanistan,” said a U.S. official who spoke on the condition of anonymity. Plus, the United States had “a lot of evidence, a lot of indicators, that there were additional attacks coming, additional attacks being planned under Mansour’s direction, aimed at our people” in Kabul.

At the same time, officials said the location and nature of the strike reflect a shifting calculation in the U.S. relationship with Pakistan, one that is less driven by the need for counterterrorism cooperation from Islamabad.

Several U.S. officials said that Obama authorized the mission in a way that would essentially confront Islamabad publicly with Mansour’s presence and presumed protection in a region of Pakistan that has been off-limits to CIA drones.

For eight years, Obama has talked about ending the war in Afghanistan. He tried a troop surge, a troop drawdown aimed at nudging Afghan soldiers into a more effective force, and finally three years of back-channel discussions aimed at goading the Taliban into peace talks.

On Saturday, by launching several missiles into a white Toyota on a well-traveled highway, Obama apparently decided it was time to try a different tactic.

“The easy answer is the war in Afghanistan is not going well, the government of Afghanistan is facing trouble, the Taliban insurgency is escalating,” said Daniel S. Markey of Johns Hopkins University’s School of Advanced International Studies. Obama, he said, “had this opportunity to take this shot, and took it.”

Pakistan’s Foreign Ministry summoned U.S. Ambassador David Hale on Monday to “express concern,” which appeared to stop well short of the formal protests that used to be routinely issued after drone strikes.

“The drone strike is different from all others because it has not only resumed a genre of kinetic action that is unilateral, but also illegal and expansionary in its geographical theater of targeted operation,” said Sherry Rehman, a senator and vice president of the Pakistan People’s Party who is a former ambassador to the United States.

Rehman and other lawmakers said they also worried that the strike — assuming Pakistani military leaders were unaware of it — means their country is becoming more isolated.

“Just five years after [bin Laden] had to be taken out, it’s now another wanted person who had to be taken out of Pakistan,” said Farhatullah Babar, a senator. “And the government of Pakistan has denied, all along, that he was even in Pakistan.”

Obama saw the dangers of targeted strikes here in April 2015, when a U.S. drone targeting al-Qaeda militants killed two hostages, including the American Warren Weinstein, in Pakistan’s tribal belt. His latest decision also seemingly conflicts with recent reports that he has been resisting calls by Pentagon leaders to authorize offensive strikes against Taliban positions inside Afghanistan.

But over the past year Obama has faced growing pressure from Afghan officials who argue that U.S. counterterrorism missions should go deeper into Pakistan.

The killing of Mansour, said Sediq Seddiqi, spokesman for Afghanistan’s Interior Ministry, shows that no Taliban leader “will be safe anywhere, even in Quetta and Pakistan, too.”

Bashir Bezhen, a Kabul-based political analyst, said Obama’s decision has helped “change the mind-set of the world and Afghans who thought that America is not serious in fighting terrorism.”

But Saifullah Mahsud, executive director of the Pakistan-based FATA Research Center, which monitors militant groups in Pakistan and Afghanistan, warned that both of those countries will soon regret Obama’s decision.

“It was pretty stupid and just jeopardizes the whole security of the region by dividing the Taliban and making them 10 times more dangerous,” he said.

If the Taliban splinters, Mahsud said, groups such as the Islamic State and al-Qaeda will fill the void.

“This just hits Pakistan in a place you are not supposed to hit people,” he said.

But U.S. officials said that Mansour’s demise should exert a strain on the Taliban and perhaps lead to defections. That would be progress, in the administration’s view, and could lead to a reconciliation between the Taliban and the Afghan government.

The airstrike “doesn’t mean the gloves come off in Pakistan,” Markey said. “But it’s likely to serve an American purpose and may help Afghanistan survive the summer.”

Miller reported from Washington. Antonio Olivo and Sayed Salahuddin in Kabul and Shaiq Hussain in Islamabad contributed to this report.