FBI Director James Comey told lawmakers Monday that his agency has been investigating possible coordination between the Trump campaign and Russian officials since last July.

The newly revealed timeline — which Comey detailed in a much-anticipated House Intelligence Committee hearing — means the FBI probe was occurring during the peak of an alleged Russian campaign to destabilize the presidential race and eventually help elect President Donald Trump.

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But Comey declined to comment on what kind of coordination or contacts between the Trump campaign and Moscow officials the FBI was examining.

He also wouldn't discuss whether the Trump team knew about any of the contacts various Trump aides have acknowledged.

Comey said he didn't know how long the investigation would ultimately take.

“There is no usually," he said. "It’s impossible to say, frankly.”

But, Comey said, just because the probe has been ongoing since July doesn't mean it's close to wrapping up.

"For a counterintelligence investigation that’s a fairly short period of time,” he said.