Warren Buffett said Monday that President Donald Trump has not contributed much to U.S. economic growth so far.

"I don't think he's had that much of an effect on the economy yet," Buffett said on CNBC's "Squawk Box." The billionaire investor supported Hillary Clinton in the 2016 election.

"I do not make investment or business decisions based on who is president or who I think is going to be president," Buffett said. "I have never called a president in my life. Never."

On Saturday, Buffett addressed tens of thousands of attendees at Berkshire Hathaway's annual meeting in Omaha, Nebraska.

The Trump administration has said proposals such as tax reform and infrastructure spending could grow the U.S. economy at 3 percent or more.

In the first quarter, the U.S. economy posted its slowest pace of growth in three years at less than 1 percent. Growth is expected to pick up slightly in coming quarters because of Trump's policies, according to Wall Street economists.

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