The Republican-led Senate Intelligence Committee on Wednesday issued a subpoena to Donald Trump Jr. to testify, signaling its Russia investigation is far from over.

Senate Majority Leader Mitch McConnell, among others, has said that any investigations into whether the 2016 Trump presidential campaign colluded with the Russians are "case closed."

Many Republicans outside the committee, as well as allies of the president, were infuriated with the subpoena and the committee's chairman, Sen. Richard Burr of North Carolina.

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WASHINGTON — Shortly after the news broke on Wednesday that the Senate Intelligence Committee had subpoenaed Donald Trump Jr., President Donald Trump's eldest son, Republicans outside the committee, as well as Trump allies, became enraged.

As Republicans, including Senate Majority Leader Mitch McConnell, were by and large declaring the investigations into Russia's election interference to be "case closed," a Republican-led committee continued to dig, causing infuriated conservatives to zero in on its chairman, Sen. Richard Burr of North Carolina.

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"Apparently the Republican chair of the Senate Intel Committee didn't get the memo from the Majority Leader that this case was closed..." Sen. Rand Paul of Kentucky wrote on Twitter.

In the House, Republicans raged against Burr for issuing the subpoena.

House Minority Leader Kevin McCarthy tweeted that Trump Jr. had "already spent dozens of hours testifying in front of Congressional committees."

"Endless investigations—by either party—won't change the fact that there was NO collusion," McCarthy said. "It's time to move on. It's time to focus on ISSUES, not investigations."

Other Republicans chimed in, expressing shock and confusion.

Rep. Lee Zeldin of New York said it was "weak & ridiculous for Senate to perpetuate the Russia Collusion Delusion by continuing to harass" Trump Jr.

"They should NOT be taking orders from unhinged resistance Dems," Zeldin added. "Let's work together to help POTUS move US forward."

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Trump's allies outside Congress were seething with rage as well.

Jason Miller, a former adviser on Trump's campaign, accused Burr of "taking marching orders from Democrats on the Senate Intel Committee & perpetuating Russia hoax."

Trump, Jr. "has already testified for over 20 hours in front of Congress and cleared by Mueller Report," Miller said. "No do-overs on 2016, Dems."

Dan Bongino, a Republican media personality who has made several attempts at running for Congress, wrote on Twitter that "Burr is not a Republican."

"He registers as one, and he runs for office as one, but the reality is that he's nothing more than a weak tool for the Democrats to use as they see fit," Bongino added. "Few 'Republican' politicians have done as much damage to conservatives as this joker."

A problem for many of the angry Republicans is that Burr has prided himself on running the Intelligence Committee and the investigation in a bipartisan fashion. And unlike many other Republicans, he also benefits from not running for reelection and having to worry about spurring a primary challenger by angering the president.