A global diamond monitoring group has found itself divided over a decision to allow Zimbabwe to sell diamonds from one of its controversial fields.

The Kimberley Process, which aims to prevent so-called “conflict diamonds” from entering the market, has approved the sale of the Zimbabwe gems from its Marange field.

However, the watchdog group is supposed to make decisions based on consensus, and some participants opposed the sale of Marange diamonds during meetings this week in Kinshasa, in the Democratic Republic of Congo.

After the meetings closed, Kimberley Process chairman Mathieu Yamba announced that Zimbabwe may export diamonds from two mines at the Marange field effective immediately.

Yamba's announcement drew objections from Western nations and rights groups that argued that human rights problems continue at Marange. They insisted Zimbabwe must not be allowed to export Marange diamonds unless the field is subject to monitoring.

The U.S. State Department said Marange diamond exports must not proceed unless the Kimberley Process reaches a consensus on the matter. The U.S. said the group's credibility is at risk and its future is at stake.

Zimbabwe's military seized the field in 2008. A year later, the Kimberly Process blocked the exports of Marange diamonds because of violence, including reports of soldiers beating and torturing villagers and forced child labor.

Earlier this week, Zimbabwe's mines minister, Obert Mpofu, told VOA his country will not allow monitoring of its diamond fields.