"He's going to have to be willing to use subpoena power, because there will be people we need to bring in before the committee who may not be willing witnesses," Schiff said on NBC News' "Meet the Press."
He said that the House Intelligence Committee will "need the power of compulsion" to investigate Russian election-related hacking "credibly."
"Right now we're the only game in town, we and the Senate Intelligence Committee," Schiff said. "We're going to have to do that."
Schiff said that he did not want to "prejudge" the committee's conclusions as to whether there is any basis for allegations of collusion between President Donald Trump's campaign and Russia.
"I would characterize it this way, at the outset of the investigation. There is circumstantial evidence of collusion. There is direct evidence, I think, of deception," he said. "And that's where we begin the investigation."
— Meet the Press (@MeetThePress) March 19, 2017