Trump allies warn Biden risking 'World War III' by authorizing long-range missiles for Ukraine

President Joe Biden for the first time authorized Ukraine to use U.S.-given long-range missiles to strike inside Russia, a prospect that President-elect Donald Trump's allies believe could threaten "World War III."

Ukraine can now target positions in the Kursk region, where Russia has lined up some 50,000 troops, including 10,000 North Koreans, senior U.S. officials confirmed to Fox News. Ukrainian forces seized the Russian territory earlier this year. 

"This is another step up the escalation ladder, and no one knows where this is going," Rep. Michael Waltz, R-Fla., Trump’s incoming national security adviser, said on Fox News. 

"​​No one anticipated that Joe Biden would ESCALATE the war in Ukraine during the transition period. This is as if he is launching a whole new war," Ric Grenell, Trump’s former acting director of national intelligence, wrote on X, formerly Twitter. 

"Everything has changed now – all previous calculations are null and void. And all for politics."

"The Military Industrial Complex seems to want to make sure they get World War 3 going before my father has a chance to create peace and save lives. Gotta lock in those $Trillions. Life be damned!!! Imbeciles!" Donald Trump Jr., the president-elect’s son, wrote on X.

ZELENSKYY: RUSSIA USING IRANIAN WEAPONS IN 'MASSIVE' ATTACK TARGETING ENERGY INFRASTRUCTURE

"On his way out of office, Joe Biden is dangerously trying to start WWIII by authorizing Ukraine the use of U.S. long range missiles into Russia," said Rep. Marjorie Taylor Greene, R-Ga., on X. "The American people gave a mandate on Nov 5th against these exact America last decisions."

Deputy national security adviser Jon Finer, in Rio de Janeiro on Monday, did not comment specifically on long-range missiles, but suggested the introduction of North Korean forces factored into the White House’s decision. 

"The United States has been clear throughout this conflict that we will make our policy decisions based on the circumstances we identify on the battlefield, including in recent days and weeks a significant Russian escalation that involves the deployment of a foreign country’s forces on its own territory," Finer said.

Ukraine has pleaded for months with the Biden administration to be allowed to strike inside Russia — and hawkish members of Congress have issued similar demands. But Biden officials feared getting the U.S. further entrenched in the war.

Rep. Thomas Massie, R-Ky., called the authorization an "impeachable offense."

"By authorizing long range missiles to strike inside Russia, Biden is committing an unconstitutional Act of War that endangers the lives of all U.S. citizens. This is an impeachable offense, but the reality is he’s an emasculated puppet of a deep state," Massie wrote on X. 

Ukrainian forces have been using drones for some deep strikes, but believe the U.S.-made ATACMS would be more effective. 

ATACMS, a surface-to-surface missile system fired from a mobile launcher vehicle, can strike anywhere between 100 and 190 miles away. 

Russian President Vladimir Putin has yet to respond to reports the U.S. will cross one of his "red lines," but his spokesperson, Dmitry Peskov, accused the U.S. of adding fuel to the fire. 

"This is a qualitatively new round of tension and a qualitatively new situation in terms of U.S. involvement in this conflict," Kremlin spokesman Dmitry Peskov told journalists in a Monday briefing. "It’s clear that the outgoing administration in Washington intends to take steps to, they’ve said so, to continue to add fuel to the fire and to further provoke the level of tension."

Ukraine has not yet used any ATACMS in Russia, according to a senior defense official. 

Rebekah Koffler, a former Defense Intelligence Agency (DIA) officer and author of "Putin’s Playbook," suggested the reports could be a "trial balloon to disrupt Trump" and Biden may not have formally authorized the ATACMS strikes yet. 

"Biden knows the danger of dragging the U.S. into conflict with Russia," she said. "But if the reports are true, then what it means to Putin is that he has been correct all along in thinking that the U.S. is serious about destroying Russia, using Ukraine, and he was correct all along to devise a plan to defeat the U.S., if necessary, with kinetic means.

"It will mean when Trump comes, Putin does not trust the U.S.… he will likely just proceed to destroying Ukraine. That is why he is not in a rush to negotiate, because he thinks that he can do it, because Russia has Ukraine outgunned and outmanned."

Trump has insisted he could bring a quick end to the war, a belief Koffler predicted Putin would play to his advantage. 

"He's going to pretend that he's interested in negotiations, and drag it on, drag it on. And you know, trying to get the best deal possible. In the meantime, he's going to proceed [with] destroying Ukraine."

DOCUMENTS REVEAL RUSSIA'S INITIAL 'PEACE DEAL' EQUATED TO THE SURRENDER OF UKRAINE: REPORT

Other congressional hawks welcomed the reported lift on restrictions, but said it had taken too long.

Sen. Roger Wicker, R-Mo., ranking member on the Armed Services Committee, said the decision "does not excuse the administration’s deliberate slow-walking of items and assistance long authorized by Congress for use against] Putin’s illegal aggression."

Rep. Mike Turner, R-Ohio, chair of the House Intelligence Committee, called the new move "long overdue," saying, "President Biden should have listened to President Zelenskyy’s pleas much earlier."

Earlier this month, Biden, for the first time, authorized U.S. contractors to deploy to Ukraine to help the country’s military maintain and repair U.S.-provided weapons systems. 

The announcement came after Great Britain and France authorized Ukraine to launch SCALP/Storm Shadow missile strikes, according to French outlet Le Figaro.

Biden's announcement also came just hours after Russia concluded one of its largest missile and drone attacks in months, launching more than 200 targeting Ukraine's power and energy infrastructure.

Putin has previously said that giving Ukraine the green light on missile use would effectively mean that the U.S. and NATO are "in the war."

"Flight assignments for these missile systems can, in fact, only be entered by military personnel from NATO countries. Ukrainian servicemen cannot do this. And therefore, it is not a question of allowing the Ukrainian regime to strike Russia with these weapons or not. It is a question of making a decision whether NATO countries directly participate in the military conflict or not," Putin said in September.

Fox News' Jennifer Griffin contributed to this report.