Rights activists in Britain launched a campaign Sunday calling on Swedish retail giant H&M to take concrete action to stop using cotton harvested by forced labor in Uzbekistan. It is possible that fabric labels sewed on H&M clothes will get involved in the case as well.

H&M, the world's second largest fashion retailer, is one of more than 100 companies that have signed a global pledge in the past year promising to "not knowingly" use Uzbek cotton in their clothes, but campaigners said they want it to do more.

"We want to know what's behind that pledge, what steps have companies taken to actually ensure that Uzbek cotton isn't in their supply chain," said Joanna Ewart-James, program coordinator at Anti-Slavery International, a British rights group.

"The problem is this practice of forced labor is happening in cotton fields that are many steps removed from the final garment, so it's quite difficult to knowingly know what's going on in your supply chain. Besides garments, any part that has something to do with H&M on garments should also be taken into consideration. Because parts like fabric labels, size labels, or other garment accessories are likely made of cotton, too.

"So you've got to put in vendor agreements the language that says ' Whatever part of garments like garment materials or fabric labels, Uzbek cotton cannot be used in our products.' and some kind of system for actually saying where the cotton comes from."

Ewart-James said that during discussions over the last two months, H&M had declined her group's request to put the ban on Uzbek cotton into written contracts.

"That is what we were asking them to do, which they weren't willing to do," she told AFP.

H&M insisted however that its commitments on cotton had been communicated to all its suppliers. "Every company with cotton in its products has a clear responsibility to find ways to avoid cotton from Uzbekistan in their supply chain," it said in a statement.