(CNN) Newly sworn-in Republican Sen. Jon Kyl said Thursday that President Donald Trump can be his "own worst enemy" at times and should keep his focus on his successes -- like the state of the economy -- and not "pick unnecessary fights."

"I haven't read the books. I haven't had very much time to catch up on all of this news that's breaking in the last 48 hours," he said, before adding that Trump could be more disciplined in the way he communicates.

"A great politician sometimes doesn't step on his own story if he's really got a good story to tell, for example. President Trump is not a politician like most the people who came to that office. He'll step on his lines sometimes," Kyl said.

Kyl, who served in the House and Senate for almost 30 years before retiring in 2013, said he was pleased when he saw a recent tweet from Trump heralding the strong economy.

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