Newt Gingrich says Trump has a 'compulsion to counterattack' "I don't think that tweet helped him," Gingrich told Raddatz on "This Week."

 -- Former House Speaker Newt Gingrich said President Trump's tweet asserting that he's under investigation for firing FBI Director James Comey wasn't helpful to the president.

"Trump has a compulsion to counterattack, and is very pugnacious," Gingrich, a strong ally of Trump, told ABC News' "This Week" Co-Anchor Martha Raddatz in an exclusive interview Sunday. "I don't think it serves him well. I don't think that tweet helped him."

But, the former GOP House Speaker added, Trump "is infuriated, and legitimately, in my judgment, by this whole Russian baloney.” Gingrich was referring to a tweet by Trump on Friday that appeared to confirm that the president is under investigation in the Russia probe.

“I am being investigated for firing the FBI Director by the man who told me to fire the FBI Director! Witch Hunt," Trump tweeted.

The president seemed to be referring to Deputy Attorney General Rod Rosenstein, who wrote a memo detailing what he saw as concerns about Comey's leadership of the FBI immediately prior to Trump's firing him on May 9.

In the letter to Comey informing him of his dismissal, the president said he was acting on a recommendation from Rosenstein. A few days later, however, in a May 11 interview, Trump told NBC News he was thinking of the Russia investigation when he ultimately made the decision to dismiss Comey.

Raddatz asked Gingrich on Sunday if the president has lost confidence in Rosenstein who, after Comey's dismissal, appointed Bob Mueller as special counsel in charge of the FBI's investigation of Russian interference in the U.S. election and possible ties to Trump associates. Gingrich didn't directly respond.

"I think he's furious," Gingrich said of the president. "I think Trump sits there and says, 'Let me get this straight, I know I didn't do anything with the Russians. Comey has said three times I didn't do anything with the Russians. Nobody on Capitol Hill has any proof I did anything with the Russians. And now I get an independent counsel who is going to mess up at least the next year.'"

Referring to an ABC News report that Rosenstein has said he may need to recuse himself from having authority over the Russia probe, Raddatz asked Gingrich if the deputy attorney general should take that action.

"No," Gingrich said. "I think this whole game of recusal now is -- this is a nightmare."