Former US National Security Adviser called Trump lawyer a "hand grenade who's going to blow everybody up."

Former US National Security Adviser warned the White House against Trump lawyer Rudy Giuliani's attempts to dig up dirt on Democratic presidential candidate Joe Biden, according to The New York Times.

Former White House official Fiona Hill described Bolton's concerns during a nine-hour testimony before Congress on Monday as part of the impeachment inquiry against US President Donald Trump.

According to Hill, Bolton called Giuliani “a hand grenade who’s going to blow everybody up.”

Bolton also called Giuliani's actions "a drug deal" and said that he had no part in their dealings with Ukraine.

Bolton was reportedly incensed that Giuliani had gone behind his back and that US ambassador to the European Union Gordon Sondland and acting White House chief of staff Mick Mulvaney were pressuring Ukraine into investigate Joe Biden and his son, Hunter Biden.

Upon learning of their actions, Bolton instructed Hill to report the situation to White House lawyer John Eisenberg.

Two associates of Giuliani were arrested last week on suspicion of campaign finance violations. The two were involved in his efforts to investigate Joe Biden in Ukraine.