The world's rich donor countries have clashed over plans to improve the quality of their overseas aid, with the US and Japan arguing against setting themselves tougher targets.

In a meeting this week in Accra, Ghana, officials have tussled over proposals to force donor countries to co-ordinate their aid programmes with each other and to use financial systems set up by the recipient developing countries wherever possible. The conference follows the so-called "Paris declaration" of 2005 in which rich governments agreed to make aid more predictable and to reduce requirements to use it to buy exports from the donor country.