The Pakistani militants who bombed a Lahore park on Easter on Sunday, killing 70 people, taunted Prime Minister Nawaz Sharif on Tuesday, declaring their war had come to his doorstep. The military has said it is hunting the Taliban's Jamaat-ur-Ahrar faction and has carried out several raids since the suicide bombing, but neither the military nor the government has given any details. Jamaat-ur-Ahrar claimed responsibility for the bombing, saying it had targeted Christians celebrating Easter and warning it would step up attacks. Lahore is the capital of Punjab, Pakistan's richest and most populous province and Sharif's political heartland. "Let Nawaz Sharif know that this war has now come to the threshold of his home," tweeted Jamaat-ur-Ahrar spokesman Ehsanullah Ehsan. "The winners of this war will, God willing, be the righteous mujahideen." Jamaat-ur-Ahrar, an independent faction of the Pakistani Taliban which and also previously declared loyalty to Daesh, has carried out five major attacks in Pakistan since December. In a televised address to the nation on Monday, Sharif vowed to continue pursuing militant groups. "I am here to renew a pledge that we are keeping count of every drop of blood of our martyrs. This account is being settled, and we will not rest till it is paid," Sharif said. The prime minister did not mention what steps would be taken in the aftermath of Pakistan's worst militant attack since gunmen stormed a Peshawar school in December 2014, killing 134 children. Military and government officials on Monday said that the military was preparing to launch a new paramilitary counterterrorism crackdown in Punjab. The move, which has not yet been formally announced, represents the civilian government once again granting special powers to the military to fight Islamist militants. "The PM ordered a joint operation of the counterterrorism department and Rangers in the border areas of Punjab against terrorists and their facilitators," said one government official who attended a meeting with Sharif and Punjab officials on Monday. Two military officials and one other government official confirmed the decision on condition of anonymity. Sharif made no mention of the crackdown in his speech, and his party has long opposed any militarized operation against militants in its heartland. The government also announced that Sharif would be canceling a planned trip to the United States to attend the Nuclear Security Summit, due to begin on Thursday. Pakistan's security agencies have long been accused of nurturing some militants to use for help in pursuing objectives in Afghanistan and against old rival India. The Pakistani Taliban are fighting to topple the government and install a strict interpretation of Islamic law. Sharif's opponents have accused him of tolerating militancy in return for peace in his province, a charge he strongly denies. Pakistan's Oscar winner pays tribute to Easter blast victims Pakistan's first Academy award winner, director Sharmeen Obaid-Chinoy, has paid tribute to victims of the Easter bombing in the eastern city of Lahore with a short film posted to her Facebook page. The 1.5-minute film titled "An Ode to Lahore, the Beautiful City" opens with a shot of the famous Badshahi mosque before showing images from the popular park where a Taliban suicide bomber blew himself up in an attack targeting Christians on Easter Sunday. At least 72 people died in the blast as families enjoyed the warm spring evening, many of them children. The bomber had walked close to a play area with swings before detonating. Chinoy, a journalist, filmmaker and activist, has won two Academy Awards for the documentaries Saving Face (2012) and A Girl in the River: The Price of Forgiveness (2015). Her video, posted Monday, showed old images of the play area before Sunday's devastation, as well as footage from a candle-lit vigil that took place for the victims in Lahore. "Lahore used to teach you to make bridges in order to reach each other," a female voice over says in Urdu as the images flit by. "We were liberal people, we were tolerant, we wanted to live with each other, we had the freedom to speak our minds." The film then displays news footage from Sunday's carnage, with images of ambulances arriving at the blast site. "We deprived our city of its personality," the voice says. Children in school uniforms are shown playing in narrow streets as they smile, before the words of the country's founding father, Muhammad Ali Jinnah, appear: "There is no power on earth that can undo Pakistan." Sunday's attack was the worst so far this year in a country grimly accustomed to atrocities, and will further undermine fractious inter-religious ties in the Muslim-majority nation. In 2012, the Government of Pakistan awarded Chinoy the Hilal-e-Imtiaz, the second highest civilian honor of the country.