Trump tweets that Susan Rice won't testify about "unmasking"

President Trump criticized Susan Rice over Twitter Thursday morning over her refusal to testify before Congress next week at a hearing related to Russian meddling in the presidential election. 

In a pair of tweets, he complained that Rice, who was Obama's last national security adviser, "is refusing to testify before a Senate Subcommittee next week on.....allegations of unmasking Trump transition officials. Not good!"

Her lawyer informed Sen. Lindsey Graham, the chairman of the Subcommittee on Crime and Terrorism, that Rice would not attend the hearing. Rice objected to the fact that she had not received a bipartisan invitation. The top Democrat on the committee, Sen. Sheldon Whitehouse, said he had not agreed to the invitation to Rice to testify, Rice attorney Kathryn Ruemmler said.

Rice said, via her attorney that she would assist Congress with its probe of Russian election interference "because of the important national interests at stake, provided they are conducted in a bipartisan manner, and as appropriate, in classified session."

While she was national security adviser, Rice requested the unmasking of some names in U.S. intelligence reports. Some were involved in the Trump presidential transition. But Rice has denied that she ever requested that a name be unmasked for political reasons. She has also denied being the source of the leak of the identity of then-National Security Adviser Michael Flynn on calls during the transition period with Russian Envoy Sergey Kislyak. 

CBS News' Julia Kimani Burnham contributed to this report