The Bush administration is being urged to investigate claims that thousands of foreign workers employed in Jordan to manufacture garments for major US companies are being severely mistreated.

The allegations are made in a new report by the National Labor Committee for Worker and Human Rights, which suggests the bi-lateral Free Trade Agreement between the US and Jordan has descended into human trafficking.

About $1.1bn worth of garments made in Jordan entered the United States duty-free last year - an increase of 2000% between 2000 and 2005 - the National Labor Committee said.

It said that tens of thousands of workers from Bangladesh, China, India and Sri Lanka are stripped of their passports and trapped in involuntary servitude, sewing clothing for Wal-Mart, Gloria Vanderbilt, Target, Kohl's, Thalia Sodi for Kmart, Victoria's Secret, and LL Bean.

109 hour weeks, shifts of up to 72 hours, sexual abuse, and workers being slapped, kicked, punched and hit with sticks and belts are just a few of the violations listed in the report.

In response to the allegations, four congressional Democrats - Reps Charles Rangel of New York, Benjamin Cardin of Maryland, Sander Levin of Michigan and Xavier Becerra of California - have written a letter to Secretary of State Condoleezza Rice and US Trade Representative Rob Portman.

Under the terms of the US-Jordan free-trade agreement, which gives Jordanian companies preferential access to the US market, both countries ensure their labour laws are consistent with international standards.