* Investors watch U.S. budget, aid to Greece, Middle East * Next week's $99 bln in supply adds selling pressure * Trading light after U.S. holiday, market to close early By Richard Leong NEW YORK, Nov 23 (Reuters) - U.S. government debt prices slipped on Friday in light post-Thanksgiving holiday trading and a reduction in safe haven demand for bonds as Wall Street stocks rose on hopes of financial support for Greece. The ceasefire between Israelis and Palestinians in Gaza also soothed some investors, who had feared the conflict spreading across the Middle East and disrupting oil supply. "Some of the safe haven trades are coming out of the bond market," said Larry Milstein, head of U.S. government and agency trading at R.W. Pressprich & Co. in New York. Despite Friday's selling, Treasury yields were squarely in the middle of their recent ranges in advance of the $99 billion coupon-bearing supply next week. The U.S. Treasury Department will sell $35 billion of two-year notes on Tuesday, $35 billion of five-year notes on Wednesday and $29 billion of seven-year notes on Thursday. On the open market, benchmark 10-year Treasury notes traded 1/32 lower in price to yield 1.685 percent, up 0.5 percent late on Wednesday. The 10-year yield was poised for its first weekly rise in five weeks. The three major U.S. stock market indexes opened higher with the Standard & Poor's 500 last up 0.6 percent. Some investors remained wary about Greece and its lenders reaching a compromise for the debt-laden country to obtain another round of financial aid. They were also skeptical whether U.S. leaders will clinch a budget deal before year-end. Steering clear of a fiscal crisis in the United States and stopping Greece going bankrupt are seen as vital to stabilizing financial markets. Investors in general have favored bonds and cash over stocks and other risky assets in the final quarter of 2012 until they believe these issues are resolved. Earlier Friday, Greek finance Minister Yannis Stournaras said the International Monetary Fund had relaxed its debt-cutting target for Greece and only a 10 billion euro ($13 billion) gap remains to be filled for a vital aid installment to be paid. In the United States, some traders bet on at least a short-term solution from U.S. President Barack Obama and lawmakers to avoid a series of automatic tax hikes and spending cuts worth $600 billion set for January. While the measures may cut the federal deficit, economists fear they could tip the world's biggest economy into recession. The White House and Congress are set to resume negotiations over contentious issues about higher taxes on the wealthy and possible reduction in social programs next week. The U.S. bond market will close early at 2 p.m. EST (1900 GMT) after it was shut on Thursday for the Thanksgiving holiday. Wall Street will stop trading at 1 p.m. (1800 GMT).