"It is puzzling that the administration would be opposed to an independent investigation of what appears to be a serious breach of national security," Cornyn said later in a statement emailed to Yahoo News.
At the hearing, Democratic Senator Patrick Leahy, the committee's chairman, said reading the New York Times reports on secret projects left him "fuming."
"I have not had a briefing yet to determine whether what was in there was accurate or not, so I'm not saying what it was, but if it was, it should not be in a newspaper," he said.
And Democratic Senator Sheldon Whitehouse raised the possibility that the leaks could be coming from executive branch officials he identified as "declassifiers" empowered to disclose secrets merely by discussing them. "As they utter classifid information it becomes declassified because they have uttered it," he said.
Feinstein announced Tuesday that she had sent Obama "a classified letter" outlining her concerns.