Washington(CNN) On the verge of his meeting with Russian President Vladimir Putin, US President Donald Trump railed against the Russia investigation and embattled FBI agent Peter Strzok, calling the agent "a disgrace to our country" and saying the probe "hurts our relationship with Russia."

Asked about the tone he expects at his upcoming summit with Russian President Vladimir Putin, Trump shifted topics, saying in a CBS News interview excerpt that "we're greatly hampered by this whole witch hunt that's going in the United States."

Trump also said he watched Strzok's House testimony last week. The President said Strzok, who had sent texts critical of Trump, was "a disgrace to our country" and "a disgrace to the FBI."

"I thought (Strzok's testimony) was an absolute disgrace. Where he wants to do things against me before I was even, I guess before I was even the candidate. It was a disgrace," Trump said during the interview at his resort in Turnberry, Scotland. "And then he lied about it. And you know, talking about shutting it down and 'we, we.' And he says, 'Oh, I meant the American people' all of a sudden, you know, he came up with excuses, I guess, given to a lawyer, but everybody laughed at it."

Trump tweeted later Sunday that he believes no matter how well the summit with Putin goes, he'll face criticism from Democrats and the media.

"Unfortunately, no matter how well I do at the Summit, if I was given the great city of Moscow as retribution for all of the sins and evils committed by Russia (...) over the years, I would return to criticism that it wasn't good enough -- that I should have gotten Saint Petersburg in addition!" Trump said in a series of tweets. "Much of our news media is indeed the enemy of the people and all the Dems (...) know how to do is resist and obstruct! This is why there is such hatred and dissension in our country -- but at some point, it will heal!"

During the hearing, Republicans charged that Strzok's texts were evidence that he was biased to clear Democratic presidential candidate Hillary Clinton and go after Trump, grilling the agent about the messages he exchanged with then-FBI lawyer Lisa Page, with whom Strzok had an extramarital affair, that led to his dismissal from special counsel Robert Mueller's team.

Strzok's role in the investigation, the President remarked, "hurts our relationship with Russia" and "a lot of countries."

"I think it's a disgrace what's going on. And then you look how, you know, partisan it is. You look at what's going on where -- and they know, they know that there's no way he can get away from those horrible texts that he wrote," Trump said. "So the other side does. But it's a very partisan thing."

Trump indicated Saturday that he had not thought of talking to Putin about the extradition of a dozen Russian military intelligence agents indicted by special counsel Robert Mueller for allegedly hacking Democrats' emails and computer networks during the 2016 election.

When asked if he would raise the issue with the Russian leader, the President told CBS News, "Well, I might. I hadn't thought of that, but certainly I'll be asking about it."