CHICAGO (CBS) — Mayoral frontrunner Rahm Emanuel is defending his use of robo-calls to call out challenger Gery Chico for having received the endorsement of a Tea Party group.

In the recorded, Spanish-language phone call, Emanuel slams Chico for receiving the endorsement of the “anti-immigrant” Tea Party. The calls refer to the Tea Party as a “right-wing group fights against President (Barack) Obama’s agenda and supports the Arizona (immigration) law,” the Chicago Tribune reported.

In Feb. 1 letter, the Chicago Tea Patriots group endorsed Chico. The letter attacked Emanuel as a “progressive liberal” who would raise taxes, and said “bringing the American tradition of free markets back to Chicago so that small businesses are free from the tyranny of Barack Obama and Rahm Emanuel’s hostile tax and spend agenda” is Chico’s top priority.

The letter also pointed out that the Chicago Police and firefighters’ unions had both endorsed Chico, and lauded Chico for his willingness to consider doing away with the law requiring city employees to live within the city limits.

But on Tuesday, another note by a different person on a separate Web site said contrary to what was reported in “media outlets,” the Chicago Tea Party Patriots had not endorsed Chico. The new letter said Chico did not espouse the values of “limited government, fiscal responsibility, individual liberty and economic freedom.”

As for Chico himself, he initially did not seek the group’s endorsement but didn’t outright reject it. “I’m more concerned with bringing people together to move our city forward,” Chico said in a statement earlier this week.

But he then did outright reject the endorsement. He said Wednesday, “I repudiate the platform of the Tea Party of Illinois,” and said he has long been a defender of immigration reform, the Chicago Sun-Times reported.

But Emanuel said the robo-calls linking Chico and the Tea Party are fair, given that Chico’s endorsement didn’t come for 24 hours after the endorsement made headlines, the Sun-Times reported.