Former US President Donald Trump strongly criticized a forthcoming book that alleges Joint Chiefs Chairman Mark Milley went behind his back to speak with Chinese military officials in the wake of the Jan. 6 insurrection.

The Washington Post on Tuesday published excerpts from associate editor Bob Woodward and national political reporter Robert Costa that alleges Milley phoned his Chinese counterpart, Gen. Li Zuocheng twice -- once on Oct. 30, 2020 and again on Jan. 8, 2021 to tell him the US would not attack.

Milley further provided assurances that he would personally inform Li ahead of any potential attack, according to the book.

- We are 100 percent steady. Everything’s fine. But democracy can be sloppy sometimes - Milley reportedly said in the second telephone call after Trump's supporters stormed the US Capitol in a failed effort to prevent US President Joe Biden's inauguration.

Milley believed Trump had fallen into mental instability after he lost to Biden in November's election by some 7 million votes, according to Woodward and Costa.

- If it is actually true,that's treason - Trump said of the allegations in the book. 

- I did not ever think of attacking China - he added during an interview with the conservative Newsmax television network.