) -- President Obama took the opportunity on Monday during a

speech about the financial crisis to address an emerging conflict with China over trade barriers.

The brawl started last week when Obama said it would impose an initial 25% tariff on tires imported from China. China responded over the weekend by announcing an investigation of complaints that U.S. auto and poultry products are hurting its own industry.

Obama said he is not advocating "self-defeating protectionism," noting that each time his administration has met with the groups of G-8 and G-20 nations, they have reiterated that pledge.

China's commerce ministry disagreed, saying in a statement that the tire tariff "not only violates WTO rules, but also runs against U.S. pledges at the G-20 summits, constitutes an abuse of trade remedy measures, and sets an extremely bad precedent in the current backdrop of a world economy in crisis."

However, Obama also noted his duty to support American industries that have suffered through hundreds of thousands of layoffs. Industries hit hard by the surging unemployment rate include tire makers like


(GT) - Get Report



(CTB) - Get Report

, automakers like

General Motors





(F) - Get Report

, and chicken producers like

Tyson Foods

(TSN) - Get Report


Sanderson Farms

(SAFM) - Get Report

, whose competitor

Pilgrims Pride

filed for bankruptcy earlier this year.

Obama also emphasized a responsibility to enforce existing trade agreements, a seeming dig at China's retaliatory investigation.

The tit-for-tat comes at a delicate time for Washington, which relies on China to purchase its currency and debt, and for Obama, who is relying on labor unions to support his sweeping health care and financial reform measures. His decision to post the added tariff arose from a complaint by the United Steelworkers that cheap Chinese tires cost them thousands of union jobs. The International Trade Commission had recommended a higher tariff of 55% in response.

Obama was required to make a decision by Thursday, ahead of a G-20 summit in Pittsburgh later this month.

-- Written by Lauren Tara LaCapra in New York