As the Democratic race heads to Nevada this weekend for caucuses there, a group of Hispanic backers of Hillary Clinton slammed the record of her rival, Vermont Sen. Bernie Sanders, on immigration issues during a conference call with reporters Thursday. The Clinton surrogates criticized instances in which Sanders voted against immigration reform and cast him as a newcomer to supporting Latinos, echoing rhetoric Clinton supporters used to critique Sanders’ support for black issues last week.

U.S. Rep. Luis Gutiérrez, D-Ill., praised Clinton as someone he has seen work on immigration issues for many years, contrasting this with what he described as Sanders being “absent for the most critical immigration debates.” He added that he stuck up for Sanders when the Vermont senator served as an independent in the House of Representatives, but Gutiérrez said he did not remember Sanders ever saying “is there something we can work on together for immigrants for Latinos?”

The Illinois congressman pointed to two bills in particular when criticizing Sanders’ record on immigration. In 2006, Sanders voted in favor a bill that would have allowed undocumented immigrants to be detained indefinitely while they awaited deportation. The same year, Sanders voted for an amendment introduced by Republicans to protect the Minutemen, an organization of heavily armed individuals who monitored the U.S.-Mexico border for people trying to illegally enter the United States.

“Bernie Sanders stood with the anti-immigrant wing of the Republican Party,” Gutiérrez said of these votes.

“Sanders has been playing for the wrong team. I want someone who has been playing for the right team,” Gutiérrez added. “I’m happy that he’s changing, but many of us have long memories that help us recognize who we can count on and who let us down when we needed them.”

Secretary of Housing and Urban Development Julián Castro, whose name has been floated as a potential vice presidential pick for Clinton, said it was “disappointing” to watch Sanders “talk up a record that just doesn’t exist.” He questioned Sanders’ priorities and values, adding that Clinton strongly supports President Barack Obama’s immigration actions such as the Deferred Action for Childhood Arrivals (DACA) and Deferred Action for Parents of Americans and Lawful Permanent Residents (DAPA) programs.

“I can say with absolute certainty that Hillary Clinton is the best candidate for us to build on President Obama’s progress,” Castro said.

The surrogates also hit Sanders over his vote against the 2007 immigration reform bill, with prominent civil rights activist Dolores Huerta saying he set the movement back a decade by not supporting the measure. “That was a devastating blow,” she said, adding, “Bernie, where have you been?”

Huerta also accused Sanders of coming to the Latino community only “now that he needs votes” and said “there is just no comparison” between Sanders and Clinton on immigration issues. This and other comments on the call were very similar to arguments African-American Clinton supporters have made in recent weeks as her campaign has aggressively courted the minority vote.

Clinton is facing an unexpectedly tough challenge from Sanders in the primary, and has seen her lead among people of color start to shrink as the campaigns have turned their attention to the diverse states of Nevada and South Carolina. After Sanders trounced Clinton in mostly white New Hampshire, the former secretary of state is counting on her popularity among African-Americans and other people of color to give her an advantage in the coming contests where states have more diverse populations.

However, enthusiasm and recent polls have indicated Nevada might be a very close race, and Clinton’s campaign has gotten nervous, lowering expectations and highlighting her support for minority communities. The Latino Victory Fund, an organization that works to politically organize Latinos, endorsed Clinton on Thursday and its president, Cristóbal Alex, praised Clinton on the call with reporters.

“Hillary is a proven leader who has always always always stood with Latinos,” Alex said, adding that the immigration positions taken by Republican front-runner Donald Trump as well as Florida Sen. Marco Rubio and Texas Sen. Ted Cruz would make America “a very scary place.”

492828616 Julian Castro, U.S. secretary of Housing and Urban Development, introduces Democratic presidential candidate Hillary Clinton at a "Latinos for Hillary" grassroots event Oct. 15, 2015, in San Antonio. Photo: Erich Schlegel/Getty Images

For his part, Sanders has also been emphasizing his support for Latinos and undocumented immigrants, and has recruited his own group of high-profile immigration leaders. His and Clinton’s supporters in the activist community battled it out on Twitter earlier this month, and the tensions have been rising since.

The Vermont senator took a hard-line stance opposing Obama’s deportation raids in early January, coming out against them before Clinton did. When a reporter asked Castro, who serves in the Obama administration, about Clinton’s response to the White House policies, Castro said he was confident in the former secretary of state’s position on the topic.

“I’m convinced is she the strongest supporter of our immigrant community but she also, as president, would have the highest likelihood of getting immigration reform done in the United States,” he said.