The largest trade union in the US has called on the Bush government to impose economic sanctions on China because of its alleged poor workers' rights.
Chinese migrant workers in Beijing
In its petition the AFL-CIO alleges some migrant Chinese workers enter into a "nightmare of 18-hour work days".
It wants the administration to impose tariffs under US law instead of going first to the World Trade Organisation.
It is the latest US union effort to draw attention to what they see as unfair working practices in China.
The 13 million-strong-union has filed its complaint with US trade representative Robert Zoellick.
Unions claim the Chinese practices have caused the loss of thousands of US factory jobs, and contributed to America's record $124bn (£68bn) trade deficit with China last year.
The AFL-CIO argues Chinese workers are cheap because the regime denies them the right to organise. Strikers and the leaders of unemployed workers' protests risk being arrested.
However, it lays particular emphasis on the working conditions it says are endured by some of China's 100 million migrant workers, who flock to the cities from the countryside to find jobs.
In its petition the AFL-CIO says these young workers, mostly female, "often step into a nightmare of 18-hour work days with no day of rest, earning meagre wages that are often withheld or unpaid altogether".
With President George W Bush going to the polls in the autumn, the union is hoping that both he and expected Democrat opponent John Kerry will be more willing to listen to its demands as they chase blue collar votes.
It wants China's alleged poor workers rights constituted as unfair labour practice, as defined in Section 301 of the US Trade Act of 1974.
However, this is the first time Section 301 has been used to challenge another country's worker practices; and since the creation of the World Trade Organisation the US normally goes there before imposing any sanctions.
Yet President Bush has been happy to act unilaterally in recent times, most notably with the introduction of tariffs against steel imports.