Trump denies Ukraine claims in former official's memoir

U.S. President Donald Trump early on Monday denied claims in a book by former National Security Advisor John Bolton that he ordered aid to Ukraine be frozen until Kiev helped in an investigation into senior Democrat Joe Biden and his son.

"I NEVER told John Bolton that the aid to Ukraine was tied to investigations into Democrats, including [former Vice President Joe Biden and his son, Hunter] the Bidens," Trump said on Twitter, adding: "In fact, he never complained about this at the time of his very public termination. If John Bolton said this, it was only to sell a book."

Trump referred to a leaked draft of Bolton's memoir, The Room Where it Happened, which is set to be released on March 17.

In his forthcoming book, Bolton reportedly claimed Trump told him in August that he wanted to keep aid to Ukraine frozen until the country helped in probes into Biden, a likely Democratic presidential rival to Trump in the approaching 2020 election.

In a series of tweets, Trump defended his presidential conduct against the allegations, the main cause of a Democrat-led impeachment trial in the U.S. Congress.

"With that being said, the transcripts of my calls with [Ukrainian] President [Volodymyr] Zelensky are all the proof that is needed, in addition to the fact that President Zelensky the Foreign Minister of Ukraine said there was no pressure and no problems," Trump said.

Trump also said Ukraine received military aid "without any conditions or investigations."

"Additionally, I met with President Zelensky at the United Nations (Democrats said I never met) and released the military aid to Ukraine without any conditions or investigations - and far ahead of schedule. I also allowed Ukraine to purchase Javelin anti-tank missiles. My Administration has done far more than the previous Administration," he added.

Trump also retweeted Sean Davis, the co-founder of The Federalist web magazine, who accused Bolton of seeking revenge against Trump, likening Bolton to former FBI Director James Comey.

"John Bolton is running the exact same revenge playbook against Trump that James Comey used. He's even using the same agent and leaking to the same reporters. All because he's mad Trump fired him for leaking and trying to start new wars. It's so boring and predictable," Davis said on Twitter.

"Just like James Comey, John Bolton is trying to get rich off of a lie- and leak-fueled campaign to overturn the 2016 election results. I suspect it will work out as well as all of Bolton's other wars," Davis added.

In a Jan. 6 statement, Bolton said he was "prepared to testify" if the Senate issued a subpoena for his testimony.

Trump is facing two separate articles of impeachment passed by the House of Representatives in December, tied to his repeated attempts to get Ukraine to declare criminal investigations into Biden and his subsequent decision to refuse to cooperate in the congressional probe into the matter.

The abuse of power article is centered on Trump's decision to hold up millions of dollars in security assistance to Ukraine as well as a coveted Oval Office meeting sought by President Volodymyr Zelensky while he was pushing to have the probes declared. The second article, obstruction of Congress, is tied to his refusal to cooperate with the congressional investigation and his directive that top officials and government agencies do the same.