The United States Trade Representative's office says it has met a World Trade Organization deadline to pull back subsidies to major American aerospace manufacturer Boeing (NYSE: BA) that had been deemed unfair, according to a Reuters report.

The WTO's March 12 conclusion found fault with U.S. government subsidies to Boeing worth $3 billion to $4 billion. The USTR said this was "mostly in the form of funding for public research."

This is the latest step in a years-long battle between the U.S. and the EU regarding government support of Boeing and rival EADS-owned Airbus. The WTO has also ruled that the EU unfairly provided more than $18 billion in subsidized funding to Airbus, according to the USTR.

Boeing claims Airbus and "its government sponsors" have "thumbed their noses at the WTO" and EU trade spokesman John Clancy announced in a statement that the EU would undertake its own investigation of whether the U.S. really has met the WTO ruling.

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