Story highlights "It worries me a great deal," Feinstein told CNN's Manu Raju

Sen. Barbara Boxer said she expressed her concern to Sanders in a phone call Tuesday

Washington (CNN) California Sen. Dianne Feinstein warned that Bernie Sanders' intention to take his candidacy to the Democratic convention in July could spark unrest similar to the chaotic 1968 convention in Chicago and the riots surrounding it.

"It worries me a great deal," Feinstein told CNN's Manu Raju. "You know, I don't want to go back to the '68 convention, because I worry about what it does to the electorate as a whole -- and he should, too."

Her comments were the latest evidence that Democrats are increasingly fretting that the divide between supporters of Sanders and backers of Hillary Clinton will be difficult to bridge in time for November's general election.

Earlier Wednesday, California's other Democratic senator, Barbara Boxer, said Sanders supporters should attempt "to change the primary process, but not to go out there and throw chairs and to put people's lives in danger because the democratic process as put forward and ratified by the two parties is being carried out."

Boxer said she felt threatened after outbursts and threats at the Nevada Democratic Convention from supporters of Sanders over the weekend.

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