Exclusive-Nuclear attack unlikely despite Putin's warnings, US intelligence says

By Erin Banco and Phil Stewart

NEW YORK/WASHINGTON (Reuters) - The U.S. decision to allow Ukraine to fire American weapons deeper into Russia has not increased the risk of a nuclear attack, which is unlikely, despite Russian President Vladimir Putin's increasingly bellicose statements, five sources familiar with U.S. intelligence told Reuters.

But Russia is likely to expand a campaign of sabotage against European targets to increase pressure on the West over its support for Kyiv, said two senior officials, a lawmaker and two congressional aides briefed on the matter.

A series of intelligence assessments over the past seven months have concluded nuclear escalation was unlikely to result from a decision to loosen restrictions on Ukraine's use of U.S. weapons. That view has not changed following President Joe Biden's changed U.S. stance this month on weapons, said the sources, who were granted anonymity to speak freely about sensitive intelligence.

"The assessments were consistent: The ATACMs weren’t going to change Russia’s nuclear calculus," said one congressional aide briefed on the intelligence, referring to American missiles with a range of up to 190 miles (306 km).

Russia's launch of a new ballistic missile last week, which analysts say was meant as a warning to Washington and its European allies, has not changed that conclusion.

One of the five U.S. officials said while Washington assessed that Russia would not seek to escalate with its nuclear forces, it would try to match what it views as U.S. escalation. The official said fielding the new missile was part of that effort.

U.S. officials said the intelligence has helped guide an often divisive debate over recent months inside Biden's administration about whether Washington loosening restrictions on Ukraine’s use of American weapons was worth the risk of angering Putin.

Officials initially resisted such a move, citing escalation concerns and uncertainty over how Putin would respond. Some of those officials, including in the White House, the Pentagon and the State Department, feared lethal retaliation on U.S. military and diplomatic personnel and attacks on NATO allies.

Others were specifically worried about nuclear escalation. Biden changed his mind because of North Korea's entry into the war before the U.S. presidential election, U.S. officials have said.

Some officials now believe the escalation concerns, including the nuclear fears, were overblown but stress that the overall situation in Ukraine remains dangerous and that nuclear escalation is not out of the question. Russia's ability to find other covert ways of retaliating against the West remains a worry.

“Russia's hybrid response is a concern,” said Angela Stent, director of Eurasian, Russian and East European studies at Georgetown University, referring to Russia’s sabotage in Europe.

“The chance of escalation was never not there. The concern now is greater.”

The White House and the Office of the Director of National Intelligence declined to comment.

The Kremlin did not immediately respond to a request for comment about the intelligence assessments.

REACTION AND COUNTER-REACTION

Since August, when Ukraine launched a surprise incursion into Russia's Kursk region, Moscow and Kyiv have been locked in a cycle of escalating moves and counter-moves.

Russia has enlisted help from North Korea, which sent between 11,000 and 12,000 soldiers to help its war effort, according to the United States.

The same day as Ukraine's first strike under the relaxed U.S. policy, Russia changed its nuclear doctrine, lowering the threshold for a nuclear strike.

Fear of nuclear escalation has been a factor in U.S. officials' thinking since Russia invaded Ukraine in early 2022. CIA Director William Burns has said there was a real risk in late 2022 that Russia could use nuclear weapons against Ukraine.

Even so, the White House moved forward with Ukraine aid, sending billions of dollars' worth of military assistance.

The concerns faded for some officials as Putin did not act on his threats but remained central to how many in the administration weighed decisions on how the U.S. should support Kyiv.

In May, the White House allowed Ukraine to use American missiles in limited circumstances to strike across the border but not deep inside Russia, citing risk of escalation by Moscow, marginal tactical benefit and a limited supply of ATACMs.

One of the intelligence assessments from early summer, drawn up at the White House's request, explained that strikes across the border from the Ukrainian city Kharkiv would have limited impact because 90% of Russian aircraft had been moved back from the border – out of distance of the short-range missiles.

But the assessments also noted while Putin often threatens to use nuclear weapons, Moscow is unlikely to take such a step in part because they do not provide a clear military benefit. Intelligence officials described the nuclear option as a last resort for Russia and that Putin would resort to other means of reprisal first, noting Russia was already engaged in sabotage and cyberattacks.

Still, some officials inside the White House and Pentagon argued that allowing Kyiv to use the missiles to strike inside Russia would put Kyiv, the U.S. and American allies in unprecedented danger, provoking Putin to retaliate either through nuclear force or other deadly tactics outside the war zone.

Pentagon officials worried about attacks on U.S. military bases.

THE NORTH KOREA FACTOR

The introduction of North Korean troops convinced the administration, particularly a group of officials at the White House and the Pentagon concerned about escalation, to allow the long-range strikes, said a senior U.S. official.

Russia was making battlefield gains and the North Korean troops were viewed internally as escalation by Moscow necessitating a response from Washington, the official said.

Given the early intelligence assessments downplaying the risk of nuclear escalation, the nuclear fears were overstated and the decision to allow wider use of ATACMs came too late, said a senior U.S. official and a lawmaker, citing Russia's recent advances.

Intelligence sources say Moscow's most robust and successful reprisal operations are likely to come through sabotage. Russian intelligence services have launched a massive international effort in Europe to intimidate countries who support Ukraine, one European diplomat said.

A U.S. official added Moscow was actively looking to advance its "gray-zone" warfare against the West and that Russia has an extensive network of agents and it exploring options for using them.

(Editing by Don Durfee and Rod Nickel)