Pakistani soldiers transport rescued school children from the site of an attack by Taliban gunmen on a school in Peshawar on Tuesday. Taliban insurgents killed at least 140 people, most of them children, after storming an army-run school in Pakistan in one of the country's bloodiest attacks in recent years. Photo: AFP

At least 140 people, most of them children, were killed on Tuesday after Taliban gunmen broke into a school in the Pakistani city of Peshawar and opened fire, witnesses said, in the bloodiest massacre the country has seen for years. 

More than eight hours after militants entered the school compound, the military declared the operation to flush them out over, and said that all nine insurgents had been killed.

Hundreds of students were taken hostage in the bloodiest insurgent attack in the country in years.

Provincial information minister Mushtaq Ghani told AFP the death toll had reached 140, with a similar number wounded. The toll was confirmed by another provincial minister.

A local hospital said the dead and wounded it had seen were aged between 10 and 20 years old.

The hard-line Islamist Taliban movement immediately claimed responsibility. It said they sent six gunmen wearing suicide vests into the building.

"We selected the army's school for the attack because the government is targeting our families and females," said Taliban spokesman Muhammad Umar Khorasani. "We want them to feel the pain."

It was not clear whether some or all of the children were killed by gunmen, suicide bombs or in the ensuing battle with Pakistani security forces trying to gain control of the building.

An unspecified number of children were still being held hostage in the school, a provincial official said, speaking some three hours after the siege began.

The Pakistani Taliban, who are fighting to topple the government and set up a strict Islamic state, have vowed to step up attacks in response to a major army operation against the insurgents in the tribal areas.

They have targeted security forces, checkpoints, military bases and airports, but attacks on civilian targets with no logistical significance are relatively rare.

According to early witness accounts, a group of militants burst into the school as students attended classes and lectures, shooting indiscriminately at both pupils and teachers.

The gunmen, who several students said communicated with each other in a foreign language, managed to slip past the school's tight security because they were wearing Pakistani military uniforms, local media reported.

Prime Minister Nawaz Sharif condemned the attack and said he was on his way to Peshawar.

"I can't stay back in Islamabad. This is a national tragedy unleashed by savages. These were my kids," he said in a statement. "This is my loss. This is the nation's loss. I am leaving for Peshawar now and I will supervise this operation myself," he said.

China has expressed its deepest condolences to the families of the victims in Pakistan and "strongly condemned the terrorist attack," according to a statement on the website of the Chinese foreign ministry on Tuesday.

"China is against all forms of terrorism, and will resolutely support the Pakistani government and its people in fighting terrorism and safeguarding national stability," the statement said.

The attack shocked the world again, one day after the hostage crisis in Sydney that Australian authorities attributed to an Islamic extremist from Iran.

Li Wei, an anti-terrorism expert with the China Institutes of Contemporary International Relations, said these are typical terrorists acts, but neither the Islamic State nor the Taliban represent Islam as a whole.

However, he pointed out that the continued emergence of Islamic extremists is a result of turmoil in the Middle East, exacerbated by the intervention by world powers. The power vacuums in some Middle Eastern countries are conducive to the spread of terrorist forces, Li said.

Li said the Taliban attack on the school in Pakistan is aimed against the Pakistan government, and is relatively isolated from other attacks of Islamic groups.

"We were standing outside the school and firing suddenly started and there was chaos everywhere and the screams of children and teachers," said Jamshed Khan, a school bus driver.

A teenage survivor described how he played dead after being shot in both legs by insurgents hunting down students to kill.

Speaking from his bed in the trauma ward of the city's Lady Reading Hospital, Shahrukh Khan, 16, said he and his classmates were in a career guidance session in the school auditorium when four gunmen wearing paramilitary uniforms burst in. "Someone screamed at us to get down and hide below the desks," he said, adding that the gunmen shouted "Allahu akbar" (God is greatest) before opening fire.

The Army Public School is attended by boys and girls from both military and civilian backgrounds.

The attack quickly drew condemnation from the international community.

Indian Prime Minister Narendra Modi branded the attack "a senseless act of unspeakable brutality" and said India shares rival Pakistan's pain.

US President Barack Obama pledged continued support for the Pakistan government's efforts "to combat terrorism and extremism and to promote peace and stability in the region."

Anthony Lake, UNICEF Executive Director, said in a statement sent to the Global Times, "The horrific, callous killing of more than 100 children today in Peshawar, Pakistan must do more than shock the conscience of the world - as it will."