The FBI has confirmed it's investigating alleged Russian government efforts to interfere in last year's U.S. election.
Investigators have also found there was no "wiretap on Trump Tower" - although they haven't ruled out the possibility that other surveillance techniques were used.
The hearing's also heard there's no evidence people's actual votes were tampered with.
Its director James Comey's been giving evidence to politicians about its inquiries.
The NSA's Admiral Mike Rogers rubbished White House suggestions that British intelligence carried out the bugging.