Donald Trump's presidential campaign is focused on "moving forward" after spending weeks defending the candidate's various controversial remarks and facing sinking poll numbers, a top aide told CNN on Sunday.

"Trump is very plugged in and he's very connected. ... The media chose to take [the] Clinton campaign narrative and go on the attack on Donald Trump," campaign chairman Paul Manafort said in an interview with Jake Tapper.

Manafort dismissed reports that Trump is exhausted and that his campaign staffers have reached peak frustration with the candidate's inability to stay on message.

Over the weekend, a New York Times report said Trump has become "often sullen and erratic" and "veers from barking at members of his staff to grumbling about how he was better off following his own instincts during the primaries."

Instead, Manafort said, "The campaign is moving forward and is very strong."

Manafort also criticized the press for covering what was seen by some as a veiled threat of violence by Trump when he suggested at a rally on Tuesday that "Second Amendment people" could stop Hillary Clinton from pursuing an anti-gun agenda as president.

"Most people did not take it that way. It was not at all meant to be a threat," he said. "You could have been covering what he was saying or you could take the Clinton narrative and play it out, and you chose to do that instead."