The accord Ronald Reagan and Mikhail Gorbachev inked in 1987 may be shredded by Donald Trump and Vladimir Putin, who each accuse the other ofviolating the Intermediate-Range Nuclear Forces (INF) Treaty.

Moscow has long claimed that the US is in breach of the deal with missile-defense installations in Romania and those planned for Poland. The US and NATO deny this.

But the ante is way up now: The US has shared what it describes as "convincing" evidence of illegal Russian actions with NATO allies and has recently begun sketching out plans for its own new medium-range missile to go into production if the INF turns out to be irrevocably scratched.

Washington would not have shared such detailed data, said one official who was only authorized to speak anonymously, unless it knew for certain that Russia had committed a serious and sizable violation.

Will presidents Putin and Trump decide that the INF treaty has outlived its relevance?

Many observers fear escalation is what lies ahead unless diplomatic efforts are stepped up in such a way as to force Moscow to come clean about its activities and destroy the illegal components.

But this would be a tall order for even the most promising of negotiations, which INF verification talks are not likely to be.

Former US Deputy Secretary of State Strobe Talbott warns that the days ahead could be the most dangerous since the weapons were destroyed.

INF an initial success

The bilateral treaty signed 30 years ago this month bans both governments from possessing ground-launched ballistic and cruise missiles with ranges between 500 and 5,500 kilometers (300 and 3,300 miles). Mechanisms in the treaty ensured the two sides destroyed their arsenals— some 2,700 missiles at the time — as well as their launchers long ago.

The INF treaty was signed in 1987 and went into force in 1988

This, it was envisioned from the US side, would neutralize Russia's ability to launch a nuclear-tipped missile that could wreak devastation in Europe, testing American resolve to defend its allies while cutting off its ability to restock Europe-based supplies.

But for years now, the US has alleged that Russia was developing a missile that violates the agreement. The Obama Administration made its suspicions public in 2014 and passed on the dossier to the Trump administration, which recently decided to provide more details.

On December 8, the US State Department published documents that officially named the missile system for the first time.

"Since declaring the Russian Federation in violation of the INF Treaty in July 2014 for the development of the SSC-8 ground-launched cruise missile system which the United States assesses to be designated by the Russian Federation as the 9M729," said one press release, "the United States has pressed Russia to return to compliance with its obligations under the Treaty."

Corresponding sanctions were placed on Russian companies believed to have contributed to building the system.

NATO: 'Serious concerns'

NATO allies, who had been briefed on the system in November in a top-secret meeting with Defense Secretary James Mattis, followed up a week later with their own joint statement, something sources say the US had pressed the alliance to produce to show the Kremlin it would not succeed in sowing transatlantic division over nuclear weapons policy.

"The United States is in compliance with its obligations under the INF Treaty and committed to strictly implementing it," the NATO statement read. "Allies have identified a Russian missile system that raises serious concerns; NATO urges Russia to address these concerns in a substantial and transparent way and actively engage in a technical dialogue with the United States."

Russian officials all the way up to President Vladimir Putin have blasted the US claims, insisting that the missile — whose very existence it confirmed in recent weeks only after the US named it publicly — is entirely compliant with the INF. Russian Foreign Ministry spokeswoman Maria Zakharova said Thursday in a tweet that Washington should quit blaming the Kremlin and instead "contribute constructively" to resolving Russian allegations of US violations.

Still, one arms control official tells DW, it was remarkable that Russia has finally acknowledged possessing the system at all, even if it hasn't yet been forthcoming about its capabilities.

That sliver of transparency may, he said, speaking off the record as he did not have authorization to speak publicly, provide an opening to discuss what exactly the missile can do and what can be done to rein it back in. This could, he explained, include reinstating an INF inspection mechanism that went dormant in 2001 after the 1980s-era arsenals were destroyed.

Nervous neighbors to nuclear weapons

Lithuania, as a neighbor to the Kaliningrad enclave where Moscow has parked some nuclear-capable Iskander-M missiles, is among the countries keeping the closest eye on Russia's nuclear pursuits.

"The Kremlin's increasing reliance on nuclear weapons in its policy calculations, its nuclear rhetoric, military concept and underlying posture is worrying," Lithuania's NATO Ambassador Vytautas Leskevicius told DW, mentioning the Iskander presence in particular.

Watch video 04:33 Share Lithuania's fence on Kaliningrad border Send Facebook google+ Whatsapp Tumblr linkedin stumble Digg reddit Newsvine Permalink https://p.dw.com/p/2gi5W Lithuania's fence on Kaliningrad border

"Taken together with concerns about Russia's new missile systems that are being developed in violation of the INF Treaty and Russia's multiple sub-strategic nuclear weapons, this introduces a high degree of uncertainty and instability."

Jon Wolfsthal has worked his entire career for theelimination of nuclear weapons, at first as the senior director for arms control and non-proliferation in the Obama National Security Council, and now as director of the Nuclear Crisis Group of Global Zero, an international anti-nuclear weapons movement. Wolfsthal says it is essential now that the two sides take this down to the technical level to see whether there actually are steps that can be taken to de-escalate both the talk and the technology.

Awaiting publication of new 'posture'

It will be tricky, Wolfstahl acknowledged. "Russia still believes apparently that it benefits from possessing this missile without withdrawing from the treaty," Wolfsthal explained. "Now the United States needs to put additional pressure [on Moscow] but also show flexibility in resolving the dispute. If the treaty is going to collapse, it must be clear that Russia is the violating party."

But even the anti-nuclear activist acknowledges that if Russia continues to obfuscate rather than obey the treaty, it "may force the United States to follow suit."

President Trump's Nuclear Posture Review, an exercise conducted by every new administration, is expected to be released next month. The administration has already made clear that it will beef up the US nuclear arsenal in significant ways. Everyone on both sides of this dispute is anxious to see how.