US takes control of tarnished blood diamonds monitor group

Obama sticks with Kimberley Process but critics slam its lack of effect on regimes

The United States has taken over the leadership of the troubled blood diamonds monitor, known as the Kimberley Process, in a move seen as the last chance to restore the credibility of the body set up to prevent the sale of gems linked to conflict and human rights abuses.

Gillian Milovanovic, a US diplomat, takes the chair less than a month after one of the body's founding partners, Global Witness, walked away, saying the monitor was "lurching from one shoddy compromise to another". It has also been accused of refusing to take action against member states including Zimbabwe.

Conceived as a certification scheme to prevent the diamond trade from being used to fund conflict, the process was accused of failing to deal with fraud in Venezuela and Ivory Coast and of appeasing the Mugabe regime.

The final straw for Global Witness came with the decision to endorse unlimited diamond exports from a region of Zimbabwe which has been the scene of mass killings by the army. At the time, the NGO's founding director, Charmian Gooch, said the disintegrating process "has turned an international conflict prevention mechanism into a cynical corporate accreditation scheme".

But the Obama administration said it would stay in the monitoring group to address the "challenges" raised by its critics. Ms Milovanovic, a career diplomat who has worked in Africa and the Balkans, must now try to restore the standing of the 76-country process that was conceived to avert any repeat of the horrors of the West African civil wars in Sierra Leone and Liberia which were largely fuelled by so-called conflict minerals.

The body itself was launched in 2003. Named after a UN meeting in the South African town of Kimberley, it is meant to ensure that uncut gems can only be traded from countries that have been certified "conflict free" – but it has been accused of using narrow definitions to avoid taking concrete action.

The hottest issue remains the Marange diamond fields in Zimbabwe, where the regime has been able to sell some £1.2bn in rough diamonds despite overwhelming evidence of horrendous human rights abuses. The military is accused of killing more than 200 people, many of them artisanal miners, in a bloody takeover of the Marange fields in 2008. Since then a number of deals have been concluded with mining companies that have helped to prop up Mugabe, despite the economic collapse of the country.