ATLANTA -- The much anticipated questioning of Sally Yates got underway midafternoon Monday by a US Senate subcommittee. Yates outlined some of what she learned about Russian ties to President Trump's former national security adviser Michael Flynn.

Yates is an Atlanta native and resident who was appointed by President Obama to high-level jobs in the Justice Department. She has stayed quite mum publicly, until now, about explosive charges she made regarding Trump adviser Michael Flynn.

She started the questioning by refusing to answer a pointed question from the Senate subcommittee chairman.

"Ms Yates, is there any evidence anyone in the Trump campaign colluded with the Russian government or intelligence services in an improper fashion?" asked Sen. Lindsey Graham (R-SC).

"Senator my answer to that question would require me to reveal classified information and so I can’t answer that," Yates responded. "I’d like to make clear, just because I say I can’t answer it, you should not draw from that an assumption that that means the answer is yes."

As acting attoney general, Yates said she met twice with the White House counsel in the early days of the Trump administration – to warn about General Flynn’s ties to Russia.

"We felt like it was critical to get this information to the White House, because the vice president was unknowingly making false statements to the public and because we believed General Flynn was compromised with respect to the Russians," Yates said.

Yates had drawn fire from Republicans because she publicly refused to enforce President Trump’s first immigration order – which banned US visits from seven mostly Muslim countries. Republicans grilled her about that Monday as well.

"We were talking about a fundamental issue of religious freedom. It was appropriate for us to look at the intent behind the president’s action and the intent as we know from was laid out in his statements" during the campaign, Yates told Sen. Ted Cruz (R-Texas), who interrupted before she could finish her answer.

Cruz and other Republicans wanted to know what gave an Obama presidential appointee authority to waive a Trump presidential order.

"Who appointed you to the United States Supreme Court," asked Sen. John Kennedy (R-Louisiana).