A group of Hispanic celebrities have signed an open letter denouncing Donald J. Trump and many of the Republican presidential candidates for “capitalizing on negative stereotypes” about Latinos to galvanize the party’s base.

The letter, put together by the People for the American Way and signed by celebrities including the actors Benjamin Bratt, America Ferrera and Zoe Saldana and the musician Carlos Santana, is one of the strongest denunciations to date by high-profile Hispanic figures of the current tone of the presidential race.

“In trying to win the nomination, every one of the leading candidates dug themselves into a deep hole pandering to the anti-immigrant base of the Republican Party that idolizes Donald Trump,” the letter says.

“There’s no coming back from this. We’ve seen clearly that all the leading Republican candidates have sided with the far-right at the expense of the Latino community,” the letter says. “They’re capitalizing on negative stereotypes and inaccurate information” for political gain.

The writers seek to prevent other Republicans from hiding their anti-immigration positions. Democrats consider Hispanic voters to be a key part of what they see as an emerging national coalition, as the party’s support from white voters has shrunk.

“This downward spiral began with Trump,” the letter says, adding, “We must not, though, let Trump’s xenophobia overshadow the extreme policies being pushed by every single one of the G.O.P.’s leading presidential candidates.”

“Trump is certainly an outlier for his racist remarks. But the rest of the Republican presidential candidates went off the deep end with him,” the letter says, also condemning the language of Jeb Bush and Senator Marco Rubio of Florida.

A spokeswoman for Mr. Trump did not respond to an email seeking comment.