Bonn: An international conference on the future of Afghanistan was overshadowed by a public display of bad blood between the United States and Pakistan, the two nations with the greatest stake and say in making Afghanistan safe and solvent.

Pakistan boycotted the conference in the German city of Bonn at which some 100 nations and international organisations, including the United Nations, jointly pledged political and financial long-term support to ensure Afghanistan's viability after international troops leave the country in 2014.

Islamabad decided not to attend the conference to protest an apparently errant US air strike last month that killed 24 Pakistani soldiers along the rough border with Afghanistan.

The strike furthered the perception in Pakistan that NATO and the US are its true enemies, not the Taliban militants that operate on both sides of the border.

 "It was unfortunate that they did not participate," U.S. Secretary of State Hillary Rodham Clinton said at a news conference.

"I expect that Pakistan will be involved going forward and we expect them to play a constructive role."

 Pakistan is seen as instrumental to ending the insurgency in Afghanistan because of its links to militant groups and its unwillingness, from the U.S. and NATO perspective, to drive insurgents from safe havens on its soil where they regroup and rearm.

Germany and the United States had once hoped the conference would showcase progress toward a political settlement between Afghanistan and the Taliban-led insurgency that 10 years of fighting by international forces has failed to dislodge. Instead, it became a status report on halting progress on other fronts and a glaring reminder that neither the Taliban nor Pakistan is ready to sign up to the international agenda for Afghanistan.