Afghan President Hamid Karzai said Thursday he hoped the shooting of a Pakistani schoolgirl by the Taliban would convince Islamabad that using extremism as a tool against others was not in its interest.

Karzai regularly accuses Pakistan of supporting Taliban Islamist insurgents trying to topple his government -- a charge Islamabad denies.

The shooting of 14-year-old Malala Yousufzai, who campaigned for the right of girls to an education, showed that Islamabad's strategy was hurting Pakistan too, he said.

"I hope this very bitter truth... has convinced our brothers and sisters, the officials in Pakistan... that using extremism as a tool against others is not in the interest of Pakistan," Karzai said.

Speaking at a joint press conference with visiting NATO Secretary General Anders Fogh Rasmussen, Karzai called on Islamabad to join him in an "honest" fight against extremism, which he said was threatening both nations equally.

The Taliban insurgency in Afghanistan "has been the consequence of safe havens on Pakistani soil", said Karzai, describing extremism as a snake which could turn and bite anyone who tried to use it against others.

Pakistan, along with Saudi Arabia and the United States, sponsored the 1980s war in Afghanistan against Soviet troops which ultimately gave rise to Al-Qaeda and the Taliban.

Islamabad was a close ally of the 1996-2001 Taliban regime, but formally sided with the United States after the 9/11 attacks that precipitated the US-led invasion which brought into power Karzai's Western-backed administration.

Yousufzai, who remains in a hospital in the UK following the shooting, came to prominence with a blog for the BBC highlighting atrocities under the Pakistan Taliban, who overran the Swat valley from 2007 until an army offensive in 2009.

NATO has more than 100,000 troops in Afghanistan backing Karzai's government against the Taliban, but they will withdraw by the end of 2014 and hand responsibility over to local forces.