House Intelligence Committee Chairman Adam Schiff rejected the GOP’s request that the panel summon Vice President Joe Biden’s son, Hunter Biden, to testify at public impeachment hearings next week.

The California Democrat also signaled he will not agree to some of the other witnesses Republicans requested Saturday, including Alexandra Chalupa, a former Democratic National Committee staffer who Republicans said worked with the Ukrainian Embassy in Washington, D.C., “to try to get political dirt on then-candidate Trump’s campaign.”