LVIV, Ukraine — (TNS) Russian troops appear close to fully capturing the key Ukrainian city of Severodonetsk, pushing them closer to their goal of taking over two eastern provinces and raising pressure on the U.S. and its European allies to quickly deliver advanced weapons systems to try to turn the tide.

Moscow’s forces have taken control of “most” of Severodonetsk, Britain’s Defense Ministry said in a briefing Thursday. Its gains follow street battles and heavy artillery bombardment that has leveled swaths of the city near the banks of the strategic Seversky Donets River.

Capture of the city could precipitate the fall of Luhansk, one of two eastern provinces bordering Russia that form the Donbas region, where the Kremlin has concentrated its military might after its failure to seize the Ukrainian capital, Kyiv.

Serhiy Haidai, Luhansk’s regional governor, said via the messaging app Telegram on Thursday that Severodonetsk had yet to fall and that Ukrainian soldiers had dislodged Russian troops from some streets. He said Ukrainian forces were in touch with some residents hiding in bomb shelters. Up to 12,000 civilians are believed to remain in the city.

Ukrainian President Volodymyr Zelenskyy said in a video address to lawmakers in Luxembourg that Russian forces now control almost 20% of Ukrainian territory and that “tens of thousands” of people have died in the first 99 days of the war.

Seeking to turn up the economic and political heat on Russia, the White House announced yet another round of sanctions Thursday targeting prominent Russian officials, oligarchs and business elites. The Department of Commerce also plans to expand its export controls on groups in Russia and Belarus in order to block access to advanced technologies needed the sustain the war effort.

U.S. officials say the war of attrition could drag on for months and that the West has little choice but to ship increasingly sophisticated military equipment to bolster Ukraine’s defense.

Kremlin spokesman Dmitry Peskov denounced the aid and its providers, saying Thursday that it would “bring more suffering to Ukraine, which is merely a tool in the hands of those countries that supply it with weapons.”

British Defense Secretary Ben Wallace said Thursday that Britain would send an unspecified number of rocket launchers able to hit targets with precision up to 50 miles away. The announcement came a day after the U.S. promised to dispatch a similar rocket system, as well as helicopters and Javelin anti-tank weapons. The systems are superior to what Ukraine — whose troops will be trained in their use — currently owns.

In addition, Germany has newly pledged to provide anti-aircraft missiles, and Slovakia said that it would send eight howitzers, though in a commercial deal rather than as military aid. Sweden also indicated its intention to donate anti-ship missiles, anti-tank weapons, semi-automatic rifles and munitions.

Russia has tried to thwart deliveries of Western arms, most recently Wednesday night when four cruise missiles fired from ships in the Black Sea struck railway infrastructure outside the western city of Lviv, causing significant damage, said Maksym Kozytsky, head of the Lviv region.

He said that five people were wounded and that four of them were hospitalized and in moderate condition. It was the latest example of Russia targeting Ukraine’s extensive rail network, which is a source of considerable pride among Ukrainians.

The strikes have wrought extensive damage and delays on a rail system that has helped transport hundreds of thousands of displaced people to safety since the war began.

A school in Kharkiv’s Kievsky district was hit by Russian shells Wednesday night, Ukrainian emergency officials said, killing one woman and injuring a man.

Sustained, indiscriminate attacks on civilian targets have taken a massive toll on Ukraine’s children, Zelenskyy said in a video address Wednesday.

He said at least 243 children have died, 139 are missing and 446 have been injured since Russia invaded Feb. 24.

“These are only those we know about,” said Zelenskyy, who was marking International Children’s Day. “We do not yet have all the information from the territory that is currently occupied.”

In addition to the casualties, Zelenskyy said an estimated 200,000 children are among the many Ukrainians who have been relocated to Russia against their will. The youngsters include those from orphanages and children separated from their parents and families.

“This is one of Russia’s most heinous war crimes,” he said. “The Russian state disperses these people on its territory, settles our citizens, in particular, in remote regions. The purpose of this criminal policy is not just to steal people, but to make deportees forget about Ukraine and not be able to return.”

In a rare bright spot for the embattled country, Ukraine defeated Scotland, 3-1, in an emotionally charged World Cup qualifying match Wednesday. The game in Glasgow was the first time the Ukrainian national men’s soccer team has appeared since the war began. The squad will advance to the World Cup in Qatar later this year if it defeats Wales on Sunday.

“Two hours of happiness,” Zelenskyy wrote in a Facebook post. “Something we are not accustomed to.”