“But the way he expressed himself is not very productive,” the diplomat said.

Mr. Karzai was interviewed on Friday, the day after he stood alongside Mrs. Clinton at the presidential palace as she warned Pakistan that it needed to crack down on militants along the Afghan border. Just a few weeks ago Mr. Karzai was in New Delhi to sign a strategic partnership with India, opening the door for it to train and equip Afghan forces to fill the void left by NATO as it gradually withdraws troops over the next three years.

Both actions further frayed relations between Afghanistan and Pakistan, which have been strained recently by cross-border rocket attacks from Pakistan and by complaints by some Afghan officials that Pakistan’s powerful spy agency had a hand in the assassination last month of the chairman of Afghanistan’s High Peace Council, Burhanuddin Rabbani, an accusation Pakistan denies.

In the interview, Mr. Karzai said Afghanistan was forever in Pakistan’s debt for welcoming millions of Afghan refugees during the last 30 years of conflict, while at the same time pleading with Pakistan to end its support for terrorists hiding out along the border areas.

“Against all the Pakistan establishment has done to Afghanistan, Afghanistan is still a brother,” he said. “Afghanistan will never forget, will never forget the welcome, the hospitality, the respect and the brotherhood shown by the Pakistan people to the Afghan people.”

His comments ignited a wave of angry calls to radio talk shows in Kabul on Sunday. Many Afghans, particularly in the north, consider Pakistan the source of much of its current troubles. One caller said, “When the president calls them brother and the nation calls them enemies, then there will be a conflict between the president and the nation.”

There was also political backlash from officials. “We must never involve ourselves in any war, particularly backing Pakistan, which is the cause of all our problems,” warned Arif Rahmani, a Parliament member from the southeastern province of Ghazni, one of the more violent and unstable regions of Afghanistan.

Mohammad Saleh Saljoqi, a Parliament member from the western province of Herat, seemed as baffled as anyone. “One day we say that Pakistan is a safe haven for the terrorists, that the Haqqani network is based there and that it is the source of a lot of our problems,” he said. “And the next day we say Pakistan is our brother country.”

The president’s comments recalled his frequent descriptions of the Taliban as our “upset brothers.”

Mr. Karzai has also frequently irked his American backers with his inflammatory comments denouncing the allied coalition. He has been particularly critical of civilian casualties, and the night raids and airstrikes that often lead to them, but he also frequently blames foreigners, and the way they deliver aid to Afghanistan, for feeding the widespread corruption that has stymied development.