U.S. senators on Tuesday criticized NATO members for failing to provide enough troops and resources to help stabilize and rebuild Afghanistan, and worried that U.S.-led operations there were losing momentum. Senate Foreign Relations Committee Chairman Richard Lugar said NATO members \"must back up\" commitments to providing security in Afghanistan \"with sufficient resources, troops, organization and political will.\" Gen. James Jones, the top U.S. commander in Europe, voiced reservations that members of the alliance would match their statements with troops and resources to help stabilize Afghanistan. \"We have had, it must be said, some difficulty in generating the military forces that support the political level of ambition,\" Jones told the committee. He said his optimism on a successful operation in Afghanistan \"would be genuine with one caveat ... that the military component of the level of ambition must be resourced and supported.\" The committee hearing came hours after a Canadian soldier with a NATO peacekeeping force and an Afghanistan civilian were killed in a suicide bomb attack near Kabul that the Taliban, said it organized. The casualties were the first among the NATO-led International Security Assistance Force (ISAF) since two Canadian peacekeepers were killed in October when their car hit a mine near Kabul. Jones said NATO members\' agreements to provide troops or equipment in some cases have become \"mired in administrative details,\" and said NATO\'s ability to expand its role in Afghanistan \"will be a defining moment\" in its post Cold War transformation. (Reuters)