The United States has been Afghanistan's biggest donor since leading the war that toppled the Taliban four years ago, but it now wants others to bear more of the "burden," US and European officials say.

Bargaining over who should shoulder the financial aid, on which the country will be dependent for a while yet, has intensified in the past months and will be taken up at the London conference.

The United States has disbursed close to $5 billion (4.1 billion euros) in this war-torn country since 2001.