WASHINGTON — A top State Department official will testify Wednesday that former National Security Advisor John Bolton warned him about Rudy Giuliani’s involvement in Ukraine in the early summer.

Bolton called President Trump’s personal lawyer a barrier to improved relations with Ukraine in a June meeting, according to the prepared remarks of Christopher Anderson, a senior diplomat deeply involved in U.S. policy toward Ukraine.

“He cautioned that Mr. Giuliani was a key voice with the President on Ukraine, which could be an obstacle to increased White House engagement,” Anderson plans to tell the House impeachment inquiry, according to copies of his prepared remarks circulated before his appearance on Tuesday.

Anderson is set to become the latest U.S. official to describe Bolton’s dim view of Giuliani’s role in Ukraine policy to the impeachment inquiry, which is focused on whether Trump pressured Ukraine to launch politically helpful investigations into Democratic targets.

Bolton once slammed Giuliani as “a hand grenade who’s going to blow everybody up,” according to the reported testimony of his former senior aide Fiona Hill, Trump’s former top adviser on Europe and Russia.

After the June 13 meeting with Bolton, Anderson summarized Bolton’s comments about Giuliani in a message to Deputy Assistant Secretary of State George Kent, who has already testified before the committees, and “sent around a more formal summary later that day to my State Department colleagues.”

Democrats are eyeing Bolton as a potentially devastating witness against the president — if he can be persuaded to appear. Dems are investigating allegations that Trump and Giuliani waged a shadow diplomacy campaign to pressure Ukraine to launch investigations that could improve Trump’s reelection chances in 2020.

Bolton has not yet been subpoenaed to appear, although his legal team has reportedly been in touch with lawyers for the House committees running the impeachment inquiry.

Anderson, who served as an aide to Trump’s special envoy to Ukraine Kurt Volker, also described an episode in which the White House blocked efforts to criticize a Russian attack on Ukraine.

“On November 25, 2018, Russia escalated the conflict further when its forces openly attacked and seized Ukrainian military vessels heading to a Ukrainian port in the Sea of Azov,” Anderson plans to say, according to his prepared remarks. “While my colleagues at the State Department quickly prepared a statement condemning Russia for its escalation, senior officials in the White House blocked it from being issued.”