Rep. Xavier Becerra (D-Calif.), a surrogate for Hillary Clinton, is bashing her rival Bernie Sanders for his “newfound advocacy” on immigration reform, calling on the Vermont senator to “explain his spotty record [and] how he’ll get it done.”

Becerra tweeted Wednesday morning that Sanders has been advocating for support of immigrant families recently but called into question his record.

We’ve been hearing a lot from @BernieSanders about supporting immigrant families of late. Where was he before he ran for president?

— Xavier Becerra (@XavierBecerra) February 17, 2016

“We’ve been hearing a lot from @BernieSanders about supporting immigrant families of late. Where was he before he ran for president?” Becerra asked in one tweet.

He called Sanders out for voting against the late Sen. Ted Kennedy’s (D-Mass.) comprehensive immigration reform bill in 2007. He also said Sanders voted for a measure designed to protect Minutemen, anti-immigrant militias on the U.S.-Mexico border.

Anyone claiming to be a defender of #immigrant families should’ve voted no. https://t.co/G7FOlANiDF

— Xavier Becerra (@XavierBecerra) February 17, 2016

The chairman of the House Democratic Caucus called on Sanders to be honest about his record, saying fixing the country’s immigration system is “tough, serious biz” and that “high-flying talk [without] a track record of action deceives those who need us most.”

If #Sanders is campaigning on immigration reform & supporting Latinos, fine. But he should explain his spotty record & how he’ll get it done

— Xavier Becerra (@XavierBecerra) February 17, 2016

To know where you’re going you must know where you’ve been. Bernie, on #immigration, where have you been?

— Xavier Becerra (@XavierBecerra) February 17, 2016

Last weekend, Sanders vowed to use executive action on immigration if he is elected president. He said at a rally in Nevada that if Congress does not address the problem, “We will use the executive powers of the White House.”