KABUL (Agencies) - Afghan President Hamid Karzai on Sunday threatened to attack Taliban insurgents on Pakistani soil, saying his war-torn country had a right to do so out of "self-defence." The warning came just days after US-led forces carried out an airstrike in Pakistan's lawless tribal belt bordering Afghanistan. Washington says it was targeting militants, but Pakistan says 11 of its soldiers were killed. It also came two days after more than 1,100 prisoners including hundreds of militants escaped from a jail in restive southern Kandahar - the birthplace of the Taliban movement - in a daring attack staged by the insurgents. "Afghanistan has the right to destroy terrorist nests on the other side of the border in self-defence," Karzai told a news conference in Kabul. "When they cross the border from Pakistan to come and kill Afghans and coalition troops, it gives us exactly the right to go back and do the same," he added, in his toughest comments yet on stamping out militancy along the border. The Afghan leader sent a specific warning to Pakistani Taliban warlord Baitullah Mehsud, whom Islamabad believes was responsible for the December assassination of former premier Benazir Bhutto. "Baitullah Mehsud should know that we will go after him now and hit him in his house," said Karzai. "Baitullah Mehsud and Mullah Fazlullah or anyone behind them must know this, that today's Afghanistan is not the voiceless Afghanistan of yesterday. Today it has both the voice, the tools and courage for action," Karzai said. Of the militants, Karzai said: "We'll defeat them and we'll avenge all that they've done in Afghanistan for the past so many years." Karzai said his administration's 'patience was running thin'. He said the cross-border attacks have destroyed homes and schools. "This is a two-way road, and Afghans are good in two-way road journeys," he said. "We will complete the journey, we will get them and we will defeat them." "Baitullah Mehsud should that know we will go after him and hit him in his house," Karzai said. He added: "The Pakistani government should know it. We will come and hit him there, wherever he is." The US-backed Afghan leader alleged that Mehsud and other Pakistani militant leaders had been trained by Islamabad's intelligence agents to fight against Pakistani Pashtuns and the Afghan people. "It is the duty of Afghanistan to relieve the Pakistani Pashtuns from this tyranny," said Karzai, himself a Pashtun. Karzai said in recent fighting in the Garmser district of Helmand province - where hundreds of US Marines have been battling insurgents for the last two months - that most of the fighters came from Pakistan. Karzai called Pakistan a 'brother government' and 'friend', but also urged it to 'act against those elements that are making Pakistan and Afghanistan insecure'. He said it was better for Afghan troops to be killed during offensive operations into Pakistan than in militant attacks in Afghanistan. Karzai said an assassination attempt against him in May and the Friday night attack by the Taliban on the Kandahar prison - an assault that freed almost 900 prisoners - underscores the challenges the country still has. The attacks are "indicative of the weaknesses that we still have. Therefore it's all the more reason for us to work harder and keep building Afghan institutions and intelligence and to be a lot more alert and steadfast in our resolve in confronting terrorism," he said. When a foreigner wanted to come to Afghanistan and fight its forces, Karzai rhetorically asked: "What should be our defence? Reading poems? Or it should be something that would rescue us?" "We will be killed here anyway, it is better that we go a step forward and kill ourselves there so that the enemies could not come after us, it is a very serious issue," Karzai said on his return from a donor conference in France. On Thursday at least 11 Pakistani troops including an officer were killed when US-led coalition forces destroyed paramilitary Frontier Corps post at Gora Prai in the tribal district of Mohmand Agency. Pakistan's military referred inquiries to the Foreign Ministry, whose spokesman, Mohammed Sadiq, said he needed to review Karzai's comments before issuing an official response. NATO's International Security Assistance Force said it was not going to comment.