Taliban militants killed 141 people — the vast majority of them children — in a sophisticated and brazen daylight attack on a military school in Peshawar that directly countered recent Pakistani government assertions that the terrorist group had been crippled by an ongoing military offensive and a series of U.S. drone strikes.
The massacre, one of the most deadly terrorist attacks ever in Pakistan, began Tuesday morning when gunmen entered an army-run school that teaches children in grades one through 10. Survivors provided harrowing accounts of militants shooting randomly, seeking out hiding students and executing wounded children.
Tehreek-e-Taliban, a Pakistani militant group, claimed responsibility for the attack. A spokesman, Mohammed Khurasani, said it was carried out to avenge the killings of Taliban members at the hands of Pakistani authorities.
“We selected the army’s school for the attack because the government is targeting our families and females,” Reuters quoted the spokesman as saying in a conference call with reporters.
President Obama condemned the attack as “heinous” and said the targeting of students and teachers showed the “depravity” of the terrorists.
Mr. Obama, who Monday marked the end of combat operations against the Taliban in Afghanistan after 13 years, also reaffirmed U.S. support for the government of Pakistan in “its efforts to combat terrorism and extremism and to promote peace and stability in the region.”
Officials said Secretary of State John F. Kerry pushed a similar message in a conversation with Pakistani Prime Minister Nawaz Sharif on Tuesday night.
Islamabad in recent months launched an offensive to stamp out the terrorist group, which operates from camps in the North Waziristan tribal area, after a siege at the Karachi international airport in June in which 10 gunmen disguised as police guards attacked a terminal with machine guns and a rocket launcher and killed 13 people during a five-hour standoff.
Michael Kugelman, senior program associate for South and Southeast Asia at the Washington-based Woodrow Wilson International Center for Scholars, said the assault was the Pakistani Taliban’s way of proving it is still capable of devising war plans and “launching horrific attacks on a very large scale.”
“This is the type of attack — today — that must have required a significant amount of preparation and advanced work,” he said.
The strike was reminiscent in its ferocity of tactics used by the extremist Islamic State group, but it was not immediately clear whether there was any connection to or influence from the group, which operates in Syria in Iraq but has been working to expand its influence in Pakistan.
“I think that the notion of the Islamic State and the Taliban cooperating is highly, highly unlikely, but I do think that the Islamic State can provide inspiration and galvanize groups like the Taliban,” Mr. Kugelman said.
After winning election last year, Mr. Sharif attempted to negotiate a settlement with the militants, who formed in 2007 as an umbrella group of factions angered over the government’s alignment with the U.S. in the war in Afghanistan. Pakistan launched a military offensive when talks broke down after the airport siege.
In September, the government indicated that the main towns in North Waziristan were under its control, and on Dec. 9 Pakistan Today reported that Mr. Sharif said the militants had been dealt a fatal blow and those displaced by the violence could return home.
David Sedney, who served as deputy assistant defense secretary overseeing Afghanistan, Pakistan and Central Asia until last year, said Islamabad now faces the choice of escalating the fight against the terrorists or renewing efforts at negotiations.
“There’s always been ambivalence among the Pakistani people about whether to militarily go after the Pakistani Taliban or use peace talks,” he said.
Mr. Sharif, who traveled to Peshawar on Tuesday, vowed that the country would not be deterred by the attack and that the military campaign would continue.
“The fight will continue. No one should have any doubt about it,” he said.
The Pakistani Taliban, which goes by the acronym TTP, is separate from but loyal to the Taliban in Afghanistan, which issued a statement Tuesday denouncing the attack, in which 132 students and nine staff members were killed. Another 121 students and three staff members were wounded.
Seven attackers, all wearing explosives vests, died in the assault. It was not immediately clear whether the militants were killed by soldiers or blew themselves up.
Human rights groups said the attack was particularly violent but fit clearly within a trend in which militants attacked more than 1,000 Pakistani schools since 2009. Many of them were schools for girls because the extremists discourage female education.
Diya Nijhowne, director of the Global Coalition to Protect Education From Attack, told BuzzFeed that “This is a particularly horrific case, in which more than 130 schoolchildren lost their lives, but it happens in a smaller scale all too often.”
The Pakistani Taliban also have targeted individual female students, perhaps most notably in 2012 when militants shot a defiant girl named Malala Yousafzai along with several of her friends.
Miss Yousafzai survived a gunshot wound to the head and this year won a Nobel Peace Prize for her outspoken resistance to such intimidation attempts.
Last month, at least 60 people were killed and over 150 injured when a suicide bomber blew himself up near the border with India, which led some to question the effectiveness of Pakistan’s military campaign.
TPP, which claimed responsibility for a failed May 2010 bombing attempt in New York’s Times Square, also has been targeted by U.S. military drone strikes.
In 2009, the U.S. killed the group’s founder and first leader, Baitullah Mehsud. Four years later, a drone strike killed Hakimullah Mehsud in a remote area of Pakistan.
Rep. Adam Kinzinger, Illinois Republican, suggested Tuesday that more U.S. aid would become available if Pakistan applies additional military pressure on the Taliban.
“Hopefully, this wakes Pakistan up to the fact that they’re going to have to cooperate with the United States, with partners in the region, to defeat this Taliban cancer once and for all,” Mr. Kinzinger said.
• Guy Taylor contributed to this article, which is based in part on wire service reports.