President Donald Trump reacted to the news that former National Security Advisor Susan Rice refused to testify to Congress about “unmasking” Trump campaign officials during the presidential campaign.

“Susan Rice, the former National Security Advisor to President Obama, is refusing to testify before a Senate Subcommittee next week on allegations of unmasking Trump transition officials,” Trump wrote on Twitter. “Not good!”

Sen. Lindsey Graham requested that Rice testify as part of the ongoing investigation into interference in the presidential election.

“Ambassador Rice respectfully declines Senator Graham’s invitation to testify,” a letter from Rice’s lawyer to Graham noted, arguing that it was “extremely rare” for Congress to request testimony from a former president’s senior staff.