Gasum, Finland's natural gas company, announced Friday that it was informed its imports from Russia's Gazprom Export will be cut off on Saturday at 7 a.m. local time.

The move by Russia comes days after Finland submitted its application to join NATO.

“It is highly regrettable that natural gas supplies under our supply contract will now be halted. However, we have been carefully preparing for this situation and provided that there will be no disruptions in the gas transmission network, we will be able to supply all our customers with gas in the coming months,” Gasum CEO Mika Wiljanen said in a statement.

Gasum will supply natural gas to its customers from other sources though the Balticconnector pipeline, which connects Finland with Estonia, the company said in a statement.

Gasum said its gas-filling stations in the network area will continue in normal operation.

-ABC News' Alexandra Faul

Dozens of artillery systems supplied by the United States to Ukraine were not fitted with advanced computer systems, which improve the efficiency and accuracy of the weapons, ABC News has learned.

The M777 155mm howitzers are now being used by the Ukrainian military in its war with Russia.

The Pentagon did not deny that the artillery pieces were supplied without the computers but said it had received "positive feedback" from the Ukrainians about the "precise and highly effective" weapons.

That positive sentiment was echoed by a Ukrainian politician, who spoke to ABC News on condition of anonymity. However, the politician also expressed frustration that the artillery pieces had not been the fitted with the digital computer systems.

Artillery is currently playing a crucial role in the fighting across eastern Ukraine, as Russia continues its offensive in that part of the country. U.S. officials recently confirmed that all but one of the 90 howitzers promised to Ukraine had now been delivered, along with tactical vehicles used to tow them.

If fitted to a howitzer, the digital computer system enables the crew operating the weapon to quickly and accurately pinpoint a target. Howitzers without a computer system can still be fired accurately, using traditional methods to calculate the angle needed to hit a target.

Modern computer systems, however, rule out the possibility of human error. Why the artillery pieces supplied to Ukraine did not have the digital targeting technology installed is unclear. The Pentagon said it would not discuss individual components "for operational security reasons."

-ABC News' Tom Burridge and Luis Martinez

As many as 1,700 Ukrainian soldiers have likely surrendered from the Azovstal Iron and Steel Works plant in war-ravaged Mariupol this week, according to the U.K. Ministry of Defense.

"An unknown number of Ukrainian forces remain inside the factory," the ministry said Friday in an intelligence update. "Once Russia has secured Mariupol, it is likely they will move their forces to reinforce operations in the Donbas."

For weeks, Ukrainian fighters and civilians were holed up inside the sprawling industrial site as the remaining pocket of resistance to Russia's relentless bombardment of Mariupol, a southeastern Ukrainian port city strategically located on the Sea of Azov between eastern Ukraine's disputed Donbas region and the Moscow-annexed Crimean Peninsula. Russia claimed Thursday that 1,730 Ukrainian soldiers had surrendered in Mariupol over the previous three days, while Ukraine confirmed Tuesday that more than 250 had yielded in the initial hours after it ordered them to do so.

Mariupol is the largest city that Russian forces have seized since launching an invasion of neighboring Ukraine on Feb. 24. Its complete capture gives Russia total control of the coast of the Sea of Azov as well as a continuous stretch of territory along eastern and southern Ukraine.

"Staunch Ukrainian resistance in Mariupol since the start of the war means Russian forces in the area must be re-equipped and refurbished before they can be redeployed effectively," the U.K. defense ministry said. "This can be a lengthy process when done thoroughly."

"Russian commanders, however, are under pressure to demonstrably achieve operational objectives," the ministry added. "This means that Russia will probably redistribute their forces swiftly without adequate preparation, which risks further force attrition."

Nearly 28,000 Ukrainian citizens have arrived in Belarus since Russia invaded neighboring Ukraine on Feb. 24, according to the Belarusian State Border Committee.

"Between 6 a.m. on February 24 and 6 a.m. on May 20, a total of 27,868 Ukrainian citizens arrived in Belarus, including 15,793 who crossed the Ukrainian-Belarusian border, 10,563 by transit through Poland, 1,305 through Lithuania, and 207 through Latvia," the committee said in a statement Friday.

In the past 24 hours alone, 154 Ukrainian citizens arrived in Belarus, including 120 via Poland, according to the committee.

Belarus shares a land border with both Ukraine and Russia, and is Moscow's main ally.

Jalina Porter, the State Department's deputy spokesperson, is responding to the Russian attack at a Ukraine train station that killed at least 50, saying, "We can no longer be surprised by the Kremlin's repugnant disregard for human life."

Five children were among those killed when Russian rockets struck the station in Kramatorsk in Donetsk Oblast on Friday morning, according to Ukraine's state-owned railway company. At least 100 people were injured, according to Donetsk Oblast Gov. Pavlo Kyrylenko.

Russia has denied involvement in the attack, which occurred as "thousands" of civilians fleeing the Russian invasion were at the train station waiting to be taken to "safer regions of Ukraine," according to Kyrylenko.

"Civilians are killed when they stay in their homes, and they're killed when they try to leave," Porter said. "Actions like these demonstrate why Russia did not belong on the U.N. Human Rights Council, and they also reinforce the U.S. assessment that members of Russian forces are committing war crimes in Ukraine."

Porter declined to say if the department considers the train station attack a war crime, saying, "Assessing individual criminal liability in specific cases is the responsibility of courts, as well as other investigatory bodies. But as the secretary, Secretary [of State Antony] Blinken, has said, 'Those responsible for war crimes and other atrocities committed in Ukraine will be held to account.'"

-ABC News' Conor Finnegan