Washington (CNN) The United States announced its formal withdrawal from a cold-war era nuclear treaty with Russia Friday as the US military is set to test a new non-nuclear mobile-launched cruise missile developed specifically to challenge Russia in Europe, according to a senior US defense official.

The US withdrawal Friday from the Intermediate-Range Nuclear Forces Treaty with Moscow puts an end to a landmark arms control pact that has limited the development of ground-based missiles with a range of 500 to 5,500 kilometers.

"Russia is solely responsible for the treaty's demise," Secretary of State Mike Pompeo said in a statement Friday announcing the withdrawal. "Russia failed to return to full and verified compliance through the destruction of its noncompliant missile system."

Meanwhile, analysts fear the US test of the non-nuclear cruise missile will mark the start of a new arms race with Moscow.

The test is expected to take place in the next few weeks and will essentially be the Trump administration's answer to Russia's years-long non-compliance with the INF treaty, the senior US defense official said.

Russia has been violating the treaty since the Obama administration; this year the Trump administration began taking steps to notify Russia and NATO that it would withdraw unless Moscow reversed course.

Russian violations

"It's been true now for two administrations, that Russia has been the one not in compliance with the treaty, not the United States," Defense Secretary Mark Esper said recently. "We have held up our treaty obligations. And we've tried to work with them over the years to get them back into compliance, but it's been to no good end."

UN Secretary General Antonio Guterres told reporters Thursday that the treaty's expiry means "the world will lose an invaluable brake on nuclear war. This will likely heighten, not reduce, the threat posed by ballistic missiles."

He urged the US and Russia to "urgently seek agreement on a new common path for international arms control."

On February 1, Pompeo announced the US would suspend its INF treaty obligations effective February 2. The Trump administration also said at the time that the US would withdraw from the treaty in six months if Russia did not return to full compliance.

In the near term, the Pentagon's planned test raises questions about whether it will be able to develop, then deploy the new missiles. Meanwhile, Russia's potential proliferation of mobile, hard to detect and quick to launch missiles that can hit Europe, Asia and even parts of the US is expected to heighten tensions and risks.

'Dramatic' implications

The implications of the INF's demise "are dramatic," said Jon Wolfsthal, director of the Nuclear Crisis Group and a former nuclear expert for the National Security Council under the Obama administration.

"Russia will continue to build and deploy intermediate range missiles that will significantly increase the risk to European allies, it will increase the risk of escalation with the United States," Wolfsthal said, "and it will increase the threat that Russia can pose in East Asia to our allies and even to Alaska, because these missiles can be deployed in the Russian far east."

Down the road, analysts say the INF Treaty's collapse leaves the world with just one agreement -- the New START Treaty -- in place to prevent the start of another Cold War-style arms race.

'More destabilizing'

The US defense official said that the US has long had evidence that Russia has developed, tested and fielded "multiple battalions" of non-INF compliant cruise and ballistic missiles. The US believes the deployments are "militarily significant" because the missiles are mobile, allowing Moscow to move them rapidly and making it difficult for the US to track them.

The Russian missiles use solid fuel, which means they can be readied in a very short time frame to fire at targets, especially in western Europe.

Alexandra Bell, senior policy director at the non-partisan Center for Arms Control & Non-Proliferation, explains that "with this type of missile there's very short warning, attacks are harder to spot by radar, so it's just more destabilizing. They made the situation in Europe more dangerous" before their elimination by the INF Treaty, she said.

The Pentagon has been working on the mobile launch system's very initial phases, which will lead to the first test in the coming weeks, the defense official said. The official emphasized there is no formal program yet to develop the missile, because the INF Treaty has been in effect.

The expected test could eventually lead to a program, the official said, but there has been difficulty in getting funding secured because of some opposition from Democrats in Congress.

The administration's budget request for fiscal year 2020, released in February, included $96 million for continued research and development on missiles with the ranges covered in the INF Treaty.

Kingston Reif, director for disarmament and threat reduction policy at the Arms Control Association, noted that in March, "the Pentagon said the plan was to test two non-INF compliant missiles later this year, after the US withdrew, the first being sometime in August."

The Pentagon also said in March that this new ground-launched missile could be ready for deployment within 18 months.

The US will likely take a current air- or sea-launched cruise missile, such as a Tomahawk, and put it on a ground-based launcher, Reif said.

"It is not a significant engineering task," said Wolfsthal. "It's well within the capability of major defense contractors and the Army to pull off."

Deployment

If the US were to proceed with developing a fully operational mobile cruise and ballistic missile system, a key unresolved question is where it would be deployed. "The hope," Wolfsthal said, is to have "a system that can be rapidly deployed in Europe or Asia."

The US has yet to formally discuss and commit to firm basing options, the senior defense official said. The concept, the official said, would be to position the missiles in militarily advantageous positions from which they could fire past Russian defenses and target the country's ports, military bases or critical infrastructure.

"Those missiles would need to be deployed in Europe to have meaningful strategic value," said Reif, referring to NATO countries. But "no alliance member has to date come forward and said it would be willing to host new US intermediate range missiles," he said.

Indeed, several NATO members, including Poland, have made clear that any deployment of the missiles in Europe would have to be approved by all NATO members. Secretary General Jens Stoltenberg has also emphasized that NATO will respond to the end of the INF Treaty as an alliance.

"What we will do will be measured, it will be coordinated as a NATO family, no bilateral arrangements, but NATO as an alliance," Stoltenberg said last month.

Reif said that any US "attempt to go around the alliance and establish a bilateral agreement with a NATO member would be a significant point of division within the alliance, one Russia would be eager to exploit."

Stoltenberg also suggested the alliance would not be amenable to US missile deployments on its border. "We will not mirror what Russia is doing, meaning that we will not deploy missiles," the NATO chief said.

When NATO defense ministers met in late June and discussed the options to ensure the alliance's security in a post-INF world, Stoltenberg said they are considering several possibilities, including additional military exercises to improve readiness, more reconnaissance abilities, air and missile defenses and conventional capabilities -- without specifying which kinds.

Moscow, meanwhile, is watching.

"Russia has said privately to me and others that if US would deploy such missiles in Europe, it would put Moscow in range ... and Moscow would have to think about pre-emption" Wolfsthal said. "That doesn't benefit European security, it only shortens the fuse to a conflict."