As Russia’s invasion continues, Ukrainian officials and two Republican members of Congress have pushed for the US to impose a no-fly zone, but doing so would be a significant escalation in the war.

In a statement to Axios on Monday, Ukrainian President Volodymyr Zelensky urged President Biden and NATO to impose a no-fly zone over “significant parts” of his country, claiming that “if the West does this, Ukraine will defeat the aggressor with much less blood.” Zelensky said in a tweet Tuesday morning that he told German Chancellor Olaf Scholz that Europeans who support Ukraine should “close the sky.”

Rep. Adam Kinzger, R-Ill., called for a no-fly zone on Friday, saying it would “disrupt Russia’s air [operations] to give the heroic Ukrainians a fair fight.” It’s either now or later.”

On Monday, Sen. Roger Wicker, R-Kan., joined him.

“Clearly, in the absence of a United Nations resolution, which Russia would veto,” Wicker told HuffPost in an interview, “a strong coalition of like-minded nations should step in and seriously consider this.”

“Tens of thousands of women and children fleeing from Kyiv west have created a humanitarian situation in which the international community must intervene and participate,” he added. According to the UN, more than 100 civilians have been killed since Russia launched its invasion last week, though the true figure could be higher.

To effectively enforce a no-fly zone, NATO would almost certainly have to shoot down any Russian aircraft that violated the declaration, an open attack on a country with nearly 6,000 nuclear weapons.

In recent decades, the United States and its allies have imposed a number of no-fly zones over countries with far less powerful militaries, such as Saddam Hussein’s Iraq in the 1990s and Libya in 2011.

The idea of establishing a no-fly zone over Ukraine does not appear to have gained traction with the Biden administration. At Monday’s White House briefing, press secretary Jen Psaki stated that enforcing one would necessitate “deploying US military to enforce, which would be… potentially a direct conflict, and potentially a war with Russia, which is something we do not intend to be a part of.”

During Monday’s Pentagon briefing, a reporter also asked Pentagon press secretary Jack Kirby if rising civilian casualties could lead to the United States implementing a no-fly zone. Kirby replied, “No,” and continued with the briefing.

That position received bipartisan support on Capitol Hill.

“There’s been a lot of loose talk from smart people about ‘close air support’ and ‘no fly zones’ for Ukraine,” Connecticut Sen. Chris Murphy tweeted. “Let’s be clear about what that is: the United States and Russia are at war.” It’s a terrible idea, and Congress would never approve it.” Military equipment for Ukraine, humanitarian assistance for Ukraine, crippling sanctions against Russia, and the movement of US troops to NATO’s eastern flank are all positive steps,” he added. “However, direct war between the world’s two nuclear powers should be ruled out.”

When asked about the possibility of a no-fly zone, Sen. Marco Rubio, R-Fla., told reporters Monday evening, “People have to understand what that means.” ”

That entails being willing to shoot down Russian planes.” That would imply World War III.”

International allies in Europe have also ruled it out. Last week, United Kingdom Defense Secretary Ben Wallace stated that imposing a no-fly zone would pit “British fighter jets directly against Russian fighter jets” and that “NATO would have to effectively declare war on Russia because that’s what you’d do.”