Rudy Giuliani won't comply with a congressional subpoena as part of the House impeachment inquiry into President Donald Trump, an attorney for Giuliani told House investigators in a letter on Tuesday.

Giuliani, the president's personal lawyer, had been subpoenaed for documents related to his work in Ukraine, which has come under intense scrutiny after Trump asked the Ukrainian president to investigate former Vice President Joe Biden and his son Hunter, NBC News reported.

Last week, two of Giuliani's business associates who had been assisting him in his Ukrainian venture were arrested on campaign-finance charges.

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