* U.S. tariff on China tires unnerves investors
* Indexes off: S&P 0.1, Dow 0.2 pct, Nasdaq 0.1 pct (Updates to late morning, adds byline)
By Edward Krudy
NEW YORK, Sept 14 (Reuters) - Wall Street slipped on Monday as a decision by the United States to impose special duties on Chinese tires sparked concerns of an escalating trade dispute.
The decision by U.S. President Barack Obama could open the door to a host of trade complaints against Chinese products, creating tensions as Western nations seek support from the world's third-largest economy at G20 meetings later this month.
In response, China's commerce ministry said Sunday it launched an anti-dumping investigation into imports of U.S. chicken products and automotive exporters.
"The fact that we've pared some of our gains this morning suggests that markets have anticipated correctly that we're going to have political pressure as far as tariffs are concerned," said Kevin Caron, markets strategist at Stifel Nicolaus & Co in Florham Park, New Jersey.
The Dow Jones industrial average was down 21.84 points, or 0.23 percent, at 9,583.57. The Standard & Poor's 500 Index was down 1.30 points, or 0.12 percent, at 1,041.43. The Nasdaq Composite Index was down 2.22 points, or 0.11 percent, at 2,078.68.
Investors are increasingly wary of stock valuations as the current rally has extended into a sixth month with the S&P 500 up 53 percent since the March 9 low.
The market was "kind of due for a dinging, a little on the overbought side here, so it's only natural for a pullback to take place." said said Stephen Massocca, managing director at Wedbush Morgan in San Francisco.
The U.S.-China row helped lift shares of U.S. tiremakers, with Goodyear Tire & Rubber Co shares up 4.2 percent to $18, and Cooper Tire & Rubber Co adding 9.8 percent to $16. (Editing by Kenneth Barry)