A visit next week to Washington by Afghan President Hamid Karzai is a chance for him to bolster international legitimacy, U.S. military officials said.

Karzai is scheduled for a Washington visit starting Monday. U.S. Army Gen. Stanley McChrystal, the top military commander for U.S. and NATO forces in Afghanistan, told The Wall Street Journal that despite a series of public spats with the Afghan president and the U.S. government, Karzai was "a very reliable partner."

Karzai came under fire in August following evidence that presidential elections were tainted by widespread fraud. Karzai, for his part, criticized Western allies for rising civilian casualties in his country, referring to international forces as occupiers at times.

War planners in Afghanistan are setting their sights on Kandahar province in the Taliban heartland in southern Afghanistan. McChrystal said the success of that operation depends on strong and working partnership between the international community and the Karzai government.

"President Karzai's relationship with the largest of the donor nations is critical," he said. "It's critical to American support for the war."

Karzai following his Washington visit convenes a tribal council meeting in late May to discuss a national reconciliation strategy that could include moderate Taliban leaders.