US President Donald Trump's nominee for a senior position in the Pentagon is facing a heated session in the Senate to ratify his appointment, because of his remarks that Democrats see as Islamophobia.

And if the Senate approves his nomination, then retired Brigadier General Anthony Tata will be Trump's strongest defender, the highest political office in the Pentagon.

Tata mistakenly described former President Barack Obama as a Muslim and accused him of being a "terrorist leader" working for Iran, according to Twitter tweets that were subsequently deleted.

The White House said it was sticking to Tata's nomination to the post of Undersecretary of Defense for policy.

He had extensive knowledge of the US military after serving nearly three decades, which included a prominent role in Afghanistan. However, current and former US military officials say he has little knowledge of Asia, at a time when Defense Secretary Mark Esber is trying to focus on competing with China.

Tata will appear before the Senate Armed Services Committee, whose Democratic members have indicated they will oppose his candidacy.

And it described Elizabeth Warren, a member of the House Democrat, Tata, as "the most incompetent and totally incompatible Trump candidate for a senior position in the Ministry of Defense by a large margin."

She added in a statement that "a person who adopts conspiracy theory and an approach that involves Islamophobia, and described President Obama as (a terrorist leader) should not occupy the third highest position in the Pentagon."