* Long-dated yields fall to day's lows after whistleblower report * Whistleblower says Trump sought Ukraine's help in 2020 election * U.S. data impact overshadowed by complaint * U.S. Treasury to sell $32 bln in 7-year notes (Adds details, analyst comment, Treasuries table, byline, updates prices) By Gertrude Chavez-Dreyfuss NEW YORK, Sept 26 (Reuters) - U.S. Treasury yields dropped on Thursday after the House Intelligence Committee released a whistleblower complaint that accused President Donald Trump of pressing a foreign government to investigate one of his main political rivals in next year's presidential election. Yields on long-dated U.S. debt fell to session lows following the release of the complaint. Overall, 10-year and 30-year yields declined in eight of the last nine sessions. The complaint said Trump pressed Ukrainian President Volodymyr Zelenskiy to investigate former Vice President Joe Biden to advance Trump's personal interest. Saying that more than six White House officials had made contact about Trump's communication with Ukraine, the report cited concerns that efforts to put pressure on Ukraine "pose risks to U.S. national security," undermining efforts "to deter and counter foreign interference in U.S. elections." "I would attribute the rally in Treasuries to the whistleblower complaint, just the concerns surrounding that," said Justin Lederer, Treasury analyst at Cantor Fitzgerald in New York. "The transcript of his call released yesterday did not seem to have anything specific that Trump said, 'do this for that.' The whistleblower complaint looks like there was more to it, but I don't know. Overall, it's just the idea that markets don't like uncertainty," he added. According to a summary of a telephone call released by the Trump administration on Wednesday, Trump pressed Ukraine's leader to investigate Democratic presidential front-runner Joe Biden, in coordination with the U.S. attorney general and Trump's personal lawyer. Earlier this week, U.S. House of Representatives Speaker Nancy Pelosi said the Democratic-led House was moving forward with an official impeachment inquiry against Trump, saying no one was above the law. Cantor's Lederer said investors are concerned about the ramifications of an impeachment inquiry, how it plays into the China trade negotiations and U.S. budget deals. In morning trading, U.S. 10-year note yields fell to 1.683% from 1.732% late on Wednesday. Yields on 30-year bonds were also lower at 2.132%, from 2.1835 on Wednesday. U.S. two-year yields were down at 1.635%, from Wednesday's 1.683%. The whistleblower complaint overshadowed U.S. economic reports that were largely in line with expectations, although some of the details were on the weak side. Gross domestic product increased at an unrevised 2.0% rate in the second quarter. It expanded 2.6% in the first half of the year. U.S. business investment though contracted more sharply than previously estimated in the second quarter and corporate profit growth was tepid. Later on Thursday, the Treasury will sell $32 billion in seven-year notes. The previous two auctions this week had mixed results: the sale of two-year notes showed strong demand, while that of seven-year notes had a lackluster outcome. September 26 Thursday 9:59 AM New York/1359 GMT Price Current Net Yield % Change (bps) Three-month bills 1.84 1.8793 -0.016 Six-month bills 1.84 1.8881 -0.018 Two-year note 99-180/256 1.6515 -0.031 Three-year note 99-194/256 1.5838 -0.035 Five-year note 99-162/256 1.5767 -0.037 Seven-year note 98-78/256 1.6348 -0.032 10-year note 99-84/256 1.6991 -0.033 30-year bond 102-16/256 2.156 -0.027 DOLLAR SWAP SPREADS Last (bps) Net Change (bps) U.S. 2-year dollar swap -1.50 0.25 spread U.S. 3-year dollar swap -3.00 1.00 spread U.S. 5-year dollar swap -7.00 0.25 spread U.S. 10-year dollar swap -12.75 0.50 spread U.S. 30-year dollar swap -43.00 1.00 spread (Reporting by Gertrude Chavez-Dreyfuss Editing by Peter Graff and Nick Zieminski)