Story highlights The hearings are likely to be overshadowed by Sessions' appearance before the Senate

But members could use it as a chance to grill Rosenstein about other topics

Washington (CNN) Deputy Attorney General Rod Rosenstein declined to say who asked him to write the letter recommending the firing of FBI Director James Comey, saying it could fall within the scope of special counsel Robert Mueller's investigation.

Rosenstein, who appointed Mueller as special counsel overseeing the probe into Russia's meddling in the 2016 election, deflected the question in a House committee hearing Tuesday afternoon.

"I am not at liberty to talk about that now, and the reason for that is that if it is within the scope of Director Mueller's investigation ... we don't want people talking publicly about open investigations," he said.

Rosenstein added that he has "no reservations about my role" in Comey's dismissal. But his comment left open the possibility that the investigation does cover the chain of events that led to Trump firing Comey.

Rosenstein said he is leaving to Mueller decisions about what the investigation covers.

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