Schumer: Trump 'really dumb' for attacking intelligence agencies

New Senate Minority Leader Charles SchumerCharles SchumerHow Trump can score a big league bipartisan win on infrastructure Overnight Finance: Dems introduce minimum wage bill | Sanders clashes with Trump budget chief | Border tax proposal at death's door GOP senators distance themselves from House ObamaCare repeal bill MORE (D-N.Y.) said Tuesday that President-elect Donald TrumpDonald TrumpPentagon chief: War with North Korea would be ‘catastrophic’ Trump campaign likely didn’t save documents: report Trump: UK prime minister 'very angry' over Manchester leaks MORE is “being really dumb” by taking on the intelligence community and its assessments on Russia’s cyber activities.

“Let me tell you, you take on the intelligence community, they have six ways from Sunday at getting back at you,” Schumer told MSNBC's Rachel Maddow.

“So even for a practical, supposedly hard-nosed businessman, he’s being really dumb to do this.”

Trump said Tuesday evening that an intelligence briefing on Russia’s cyber activities “was delayed until Friday" and suggested that intelligence agencies weren't prepared. NBC News reported, however, that the briefing was always planned for Friday.

"The 'Intelligence' briefing on so-called 'Russian hacking' was delayed until Friday, perhaps more time needed to build a case. Very strange!" the president-elect wrote on Twitter.

Intelligence officials have reportedly determined that Russia tried to interfere in the U.S. presidential election to help Trump win the White House. President Obama has ordered a full report on the issue, and last week he put in place new sanctions against Russian intelligence organizations and individuals, in addition to expelling 35 Russian officials from the country and closing two stateside facilities used by the Russians for intelligence purposes. 

Trump’s transition team responded to the initial reports about the CIA's findings by drawing comparisons to its intelligence about supposed weapons of mass destruction in the lead-up to the invasion of Iraq. 

Schumer said that as he understands, intelligence officials are "very upset with how [Trump] has treated them and talked about them."