U.S. experts have warned that Afghanistan risks becoming a failed state if urgent steps are not taken to improve security and reconstruction in the country.

In a report issued Wednesday, former Ambassador Thomas Pickering and retired Marine Corps General James Jones called for NATO to increase troop levels, and for the U.S. government to appoint a special envoy for Afghanistan.

The report warns that reconstruction efforts and civil reforms are seriously threatened by increased insurgent violence, weakening international support, and a lack of confidence among the Afghan people.

Also Wednesday, President Bush spoke with Canadian Prime Minister Stephen Harper to discuss Afghanistan. A White House spokesman said the two leaders discussed the requirements to sustain the current mission and how to ensure its continued success.

Canadian officials say Mr. Harper told the president that Canada might remove its troops from Afghanistan next year unless NATO sends in more troops to fight Taliban insurgents.

On Monday, Mr. Harper said he accepts the broad recommendations of the independent Manley Panel, which said Canada should withdraw its 2,500 troops from violence-plagued Kandahar province unless NATO sends in extra soldiers and equipment.

The refusal of some European NATO allies to send troops to Afghanistan's dangerous east and south has created rifts with Britain, Canada and the Netherlands, which, along with the United States, have suffered the most casualties from Taliban violence.

Some information for this report provided by Reuters and AFP.