(CNN) —  

Former San Antonio Mayor Julián Castro said he plans to release 10 years of his tax returns as part of his 2020 Democratic presidential bid.

“I’m going to release 10 years of tax returns with plenty of time for people who are going to go caucus in Iowa and then of course everybody who’s going to vote after to digest them,” he told CNN’s Brianna Keilar in an interview on “Right Now” Friday.

Castro did not specify when he would release his tax returns. His campaign told CNN that he does not plan on releasing his taxes until they’ve been filed this year. The tax season ends on April 15.

Castro called on President Donald Trump, who’s claimed he’s under audit by the IRS, to release his tax returns.

“He clearly doesn’t want us to see something there and hopefully Congress will be able to get a hold of them,” Castro said.

New York Sen. Kirsten Gillibrand, Massachusetts Sen. Elizabeth Warren and Washington Gov. Jay Inslee have already disclosed their personal tax returns in what could become a litmus test for Democratic candidates. Vermont Sen. Bernie Sanders promised in February to release his tax returns “soon.”

Castro, the only Latino candidate running, also criticized Trump’s rhetoric and policies on immigration.

“We have right now a border that is more secure than it’s ever been,” Castro told Keilar on Friday. “The thing is that this President wants us to believe that we have to choose between a secure border and compassion. His cruelty has failed. And I believe that we should choose compassion and still have a secure border.”

Castro accused Trump of deflecting attention to immigration and “scapegoating immigrants” whenever he’s in “political hot water.”

“And I’m done with buying the BS narrative that young children and women and families present a national security threat to this country. They do not,” Castro said.

The presidential hopeful unveiled a detailed immigration plan this week that would provide a path to citizenship for Dreamers and treat illegal entry into the US as a civil rather than a criminal violation.

Castro — one of 17 Democrats in the 2020 field — also told CNN he has not yet met the Democratic National Committee’s requirement of 65,000 individual donors to qualify for the first debate in June.

CNN’s Dan Merica contributed to this report.