Karzai told journalists in Kabul that as long as Pakistan-based insurgents attack Afghanistan, destroy its infrastructure, and kill its children, the Afghan government equally has the right to target Taliban leaders and bases inside Pakistan.
"Afghanistan has the right of self defense," he said. "When [the Taliban] cross the territory from Pakistan to come and kill Afghans and to kill coalition troops, it exactly gives us the right to go back and do the same."
Karzai cited the names of several Pakistani Taliban leaders and warned that they could be targeted in their homes.
"Baitullah Mahsud should know that we will go after him now and hit him in his house," Karzai said. "Fazlullah should know the same that we will go after him and hit him in his house and in his bases. And the other fellow, Mullah Omar of Pakistan, should know the same. This is a two-way road in this case and Afghans are good in the two-way road journey. We will complete the journey and we will get them and we will defeat them and we will avenge all that they have done in Afghanistan for the past so many years."
However, Karzai made it clear that Afghanistan has no desire to fight against the people of Pakistan. And he argued that any Afghan efforts against the Pakistan-based Taliban would help liberate Pashtuns in Pakistan from the tyranny of terrorism.
Some 30 million Pahtuns live in Pakistan, concentrated mostly along the border with Afghanistan and with some living in territories now controlled by Taliban.
Karzai said that "Baitullah Mahsud, Mullah Omar of Pakistan, and Fazlullah all are the creation of Pakistani intelligence agencies together with some Pashtuns of Pakistan and some Afghans."
He said that "these people have been tasked with burning schools in the Pashtun regions of Pakistan, preventing their daughters from going to schools, destroying their livelihoods, killing the Pashtun tribal leaders in Pakistan."
And he added, "It is the duty of Afghanistan to liberate the Pashtuns of Pakistan from a life of tyranny and terror."
In Pakistan, Prime Minister Yousuf Raza Gilani said his country will not allow anyone to interfere in its affairs.
Speaking to AP, Gilani said the Afghan-Pakistan border is too long to prevent people from crossing, "even if Pakistan puts its entire army along the border."
The NATO-led International Security Assistance Force (ISAF) said it will not comment on the issue.
Tensions between the Afghan and Pakistani governments have been rising in recent months as the Pakistani government engages in a cease-fire and negotiates peace deals with Pakistani Taliban leaders. Afghan authorities and NATO have repeatedly complained about an increase in cross-border attacks following the Pakistani peace deals.
In recent days, ISAF has stepped up their efforts to target Taliban fighters in the Pakistan border region.
AFP reported that a missile strike in the village of Makeen in Pakistan’s insurgency-plagued South Waziristan tribal district killed one militant on June 14. Pakistani officials told the news agency that an unmanned drone aircraft reportedly launched the strike after coming under fire.
On June 11, the U.S.-led coalition forces bombed fleeing Taliban insurgents in Pakistan’s Mohmand tribal districts. The air strike brought criticism from the Pakistani government, which says the bombs did not kill insurgents but instead 11 paramilitary soldiers.
Washington has expressed regret over the loss of Pakistani life, but has not taken responsibility for the deaths.
Rizwan Murad and Safia Hassas of RFE/RL's Radio Free Afghanistan reported this story from Kabul