Analysts said they doubt military action by Afghanistan is imminent, but Pakistan's prime minister said the threat "will not be taken well." A Taliban spokesman warned that the Afghan army would be defeated by thousands of armed tribesman.

Speaking on the grounds of his fortified presidential palace, Karzai told a news conference that Afghanistan has the right to self defense, and because militants cross over from Pakistan "to come and kill Afghan and kill coalition troops, it exactly gives us the right to do the same."

Then, Karzai warned Pakistan-based Taliban leader Baitullah Mehsud that Afghan forces would target him on his home turf. Mehsud has been accused in last year's assassination of former Pakistani Prime Minister Benazir Bhutto.

"Baitullah Mehsud should know that we will go after him now and hit him in his house," Karzai said.

"And the other fellow, (Taliban leader) Mullah Omar of Pakistan, should know the same," Karzai continued.