The United States would ban the import and export of diamonds used to fund civil wars in Africa under a bill approved by a Senate panel on Wednesday.

The legislation adopted by the Senate Finance Committee brings the United States into an international agreement to ban trade in so-called conflict diamonds.

The agreement, known as the Kimberley Process, includes representatives of the diamond industry, human rights groups and dozens of other nations. The group requires that traded diamonds come with certification that they were mined from legitimate sources.

Human rights groups say rebels in Sierra Leone and Angola use forced labor to mine diamonds, which are sold to finance the rebels' military efforts. Purchasers then resell the diamonds for a profit.

It is estimated that conflict or "blood" diamonds make up less than 4 percent of the annual global diamond trade.