Oil prices tumbled more than $4 per barrel today as President Bush held out the possibility of a diplomatic solution to the Persian Gulf crisis. Contracts for light sweet crude fell more than $1 per barrel in a span of several minutes while Bush was on television giving his assessment of the crisis. His remarks followed a vote late Thursday in which the U.N. Security Council authorized the use of force to push Iraqi troops out of oil-rich Kuwait if Iraqi President Saddam Hussein does not withdraw them by Jan. 15. Crude then kept falling sharply, sinking below the $30 per barrel threshold, after Bush's news conference had ended. By late afternoon, contracts for crude delivery in January were down $4.21 per barrel, at $28.70, on the New York Mercantile Exchange. Oil's biggest move during the crisis was a fall of $5.41 per barrel on Oct. 22. Contracts for crude delivery in several later months were down by their daily limit of $1.50 per barrel. Bush said he would invite Iraqi's foreign minister, Tariq Aziz, to come to Washington in December to discuss the situation. Bush also mentioned the possibility that he would send Secretary of State James A. Baker III to Baghdad, the Iraqi capital. ``The reaction is very much to his inviting Tariq Aziz to Washington and Baker to Baghdad,'' said Ann-Louise Hittle, a senior oil analyst with Shearson Lehman Brothers Inc. The market had moved up earlier in the week in anticipation of the U.N. resolution, so Bush's comments indicating that he would send troops into combat if necessary did not move the market. The president said he would accept nothing less than a complete withdrawal of Iraqi troops and freedom for hostages held by Saddam. ``This has been a war premium market,'' Hittle said. ``We rose on expectation of the U.N. resolution being passed. With his comment today, we're losing that war premium and backing off.'' As oil plummeted, prices for refined petroleum products also fell. By early afternoon, home heating oil was down 6.42 cents at 87.10 cents a gallon on December delivery contracts. Unleaded gasoline fell 5.12 cents a gallon to 78.25 cents on December delivery contracts. Some of the contracts for product delivery in later months were down by their daily limit of 4 cents a gallon. Natural gas was off 7.5 cents at $2.415 per 1,000 cubic feet on contracts for delivery in January.