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North Korean troops' involvement escalates conflict,

prompts

U.S. policy shift

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Biden aims to 'Trump-proof' Ukraine policy before Jan. 20

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inauguration

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Move may come too late to alter course of war, but could

help

Ukraine hang on to Kursk

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By Mike Stone, Humeyra Pamuk and Matt Spetalnick

WASHINGTON, Nov 21 (Reuters) - President Joe Biden

dropped his opposition to Ukraine firing U.S. missiles at

targets deep inside Russia in response to North Korea's entry

to the war, a shift in U.S. policy that took on added urgency

following Donald Trump's Nov. 5 election win, sources familiar

with the matter said.

Biden for months resisted pleas from Ukrainian President

Volodymyr Zelenskiy to ease limits on the use of U.S.-supplied

ATACMs missiles, which can reach far into Russian

territory, wary of potentially drawing NATO into a conflict with

a nuclear-armed power.

But Moscow's decision to deploy North Korean soldiers to

Russia's Kursk region represented a major escalation that

demanded a response, a senior U.S. official and two other

sources familiar with the matter told Reuters.

The election of Trump - who is deeply skeptical of U.S.

support for Ukraine - added pressure on the administration to

loosen the rules on the use of the weapons and take other steps

to bolster Ukraine as it suffers repeated setbacks on the

battlefield, said two other sources familiar with the matter.

The decision could help to "Trump-proof" parts of Biden's

Ukraine agenda by strengthening Ukraine's position in case they

lose U.S. support, one of the sources said.

Trump has repeatedly criticized U.S. military aid to

Ukraine, raising fears that he might suspend weapons supplies.

The relaxation of the restrictions on U.S. weapons may have

come too late to alter the course of the conflict but could help

Ukraine defend the foothold it has in Kursk.

The White House did not immediately respond to a request for

comment.

A State Department spokesperson declined to say whether

Biden had authorized the longer-range strikes but said Russia

was escalating the conflict by deploying North Korean troops.

Moscow has vowed to respond to what it sees as an escalation

by the West. A U.S. official said on Thursday that Russia may

have fired an intermediate-range ballistic missile during an

attack on the Ukrainian city of Dnipro, in a likely warning to

NATO.

STRENGTHENING KYIV'S HAND

The relaxation of U.S. conditions was conveyed to Ukraine

during a Nov. 12 call between Secretary of Defense Lloyd J.

Austin III and Ukrainian Minister of Defense Rustem Umerov, said

a source familiar with the discussions.

A day later, Secretary of State Antony Blinken informed NATO

Secretary-General Mark Rutte and European officials of the

decision as well as his Ukrainian counterpart, Andrii Sybiha,

during a trip to Brussels, a senior U.S. official said.

Ukraine conducted its first long-range strike under the new

policy on Tuesday, announcing it had fired U.S. ATACMS missiles

on an arms depot about 110 km (70 miles) inside Russia.

Biden's easing of weapons restrictions appeared to open the

door for U.S. allies to allow their own weapons to be used in

new ways. On Wednesday, Ukraine fired a volley of British Storm

Shadow cruise missiles into Russia.

Since the elections, the Biden administration has taken

other actions to support Kyiv, approving the use of

anti-personnel mines to slow Russia's advance in Ukraine's east

and allowing U.S. defense contractors to work inside Ukraine to

repair U.S.-supplied weapons, enabling the Ukrainians to keep

more of the gear in active use.

For months, Ukrainian officials pleaded with Americans to

let them use the 190-mile range rockets for targets deeper

inside Russian territory, arguing that their inability to hit

air bases hosting warplanes involved in strikes on Ukraine was a

major handicap.

But the Biden administration declined to give a green light.

U.S. officials have been skeptical of the value of letting

Ukraine use weapons such as the ATACMs, arguing that Moscow has

already moved some bombing targets out of range, and that

Ukraine already has domestically made rockets and kamikaze

drones that can reach into Russian territory.

They have also worried that such a move could risk a

direct war between NATO and Russia, a possibility some experts

and U.S. lawmakers have downplayed.

Russia's decision to deploy thousands of North Korean troops

to join the fighting changed the administration's thinking.

The U.S. acknowledged in late October that it had seen

evidence of North Korean troops in Russia for possible

deployment in the Ukraine conflict.

North Korean soldiers had docked in the eastern port

city of Vladivostok, after boarding ships in early-to-mid

October from North Korea's Wonsan region, and were taken to

three military training sites in eastern Russia, White House

spokesperson John Kirby told reporters.

The following week Blinken said as many as 8,000 North

Korean forces were in Kursk, where Ukrainian forces have

controlled territory since August.

Easing U.S. controls on the use of the missiles was

intended to send a message to the North Koreans and Russians

that the shift was unacceptable, as well as hamper their efforts

to push Ukrainians out of Kursk, said a senior U.S. official

familiar with the administration's thinking.

The official acknowledged that relaxing the restrictions

risked a further escalation of the conflict - but noted that

Russia has so far taken no action against states other than

Ukraine.

And a congressional aide said they believed the new policy

only applied to the Kursk region.

"Ukraine is only authorized to shoot deeper into Russia to

constrain the Russian-North Korean effort to push Ukraine out of

the Russian territory," the aide said.