News said the president called for the increase after he was shown a chart indicating the stockpile of U.S. nuclear weapons had slid from a high of 32,000 in the 1960s.
Last week, Trump similarly blasted NBC News as "fake" after it reported that Tillerson called Trump a "moron". Schatz raised the possibility of the White House interfering with the FCC's affairs and questioned Chairman Pai about any inappropriate contact the FCC may have had with the White House.
"I never said that", he said during a news briefing with Canadian Prime Minister Justin Trudeau. "If you want me to weigh in against one entity, you can ask the whole Virginia delegation - we won't hardly speak to the Washington Post anymore".
After Trump's tweet targeting NBC on Wednesday, CNN anchor Jake Tapper replied to the president with a picture of the First Amendment.
He called the report "pure fiction" that was "made up to demean".
The president's suggestion is unlikely to do much to ease his frustrations.
"Fake @NBCNews made up a story that I wanted a "tenfold" increase in our USA nuclear arsenal", Trump wrote. The president reportedly remarked Wednesday: "It is frankly disgusting the press is able to write whatever it wants to write".
In February, Trump said he was going to build up the USA nuclear arsenal to ensure it is at the "top of the pack", and said the US has fallen behind in its atomic weapons capacity. The FCC issues broadcast licenses to stations. Comcast, which owns NBC, owns several licenses in major markets such as NY and Los Angeles.
"People should look into it".
The news comes at a time when Trump is expected within days to declare that Iran is not fulfilling its obligations under a 2015 anti-nuclear-proliferation deal it made with the Obama administration.