Waves of Russian missiles pounded a military training base in western Ukraine on Sunday, killing 35 people in an attack on a facility that served as a crucial hub for cooperation between Ukraine and the countries of NATO which supported it in its defense against the brutal attack of Moscow.

More than 30 Russian cruise missiles have targeted the sprawling facility, which sits not far from the border with NATO member Poland and has long been used to train Ukrainian military personnel, often with instructors from the United States and other Western Alliance countries.

Poland is also a transit route for Western military aid to Ukraine, and the strikes followed threats from Moscow to target those shipments.

An attack so close to the border was fraught with symbolism in a conflict that has reignited old Cold War rivalries that gave birth to NATO and threatened to rewrite the current global security order.

Since Russia’s invasion more than two weeks ago, at least 596 civilians have been killed, according to the UN, although it estimates the true toll to be much higher. Millions more have fled their homes amid Europe’s biggest land dispute since World War II.

Despite its superior firepower, Russia struggled to advance through Ukraine, facing stronger-than-expected resistance, bolstered by Western weaponry support.

Instead, Russian forces besieged and pounded several towns, hitting two dozen medical facilities and leading to a series of humanitarian crises.

(PA graphics)

Many civilians were caught in the barrage, and Ukraine’s prosecutor general’s office said on Sunday that at least 85 children had been killed.

A US journalist was killed and another injured when their car was shot at a Russian checkpoint on Sunday, police said.

Meanwhile, US President Joe Biden is sending his national security adviser to Rome to meet with a Chinese official on Monday amid fears the country is amplifying Russian disinformation, and Pope Francis has called for peace.

The training base that was attacked is near Yavoriv, ​​less than 25 km from the Polish border and appears to be the westernmost target hit during the 18-day Russian invasion.

The base has hosted international NATO exercises and a senior NATO official, Admiral Rob Bauer, has previously hailed it as embodying the “spirit of military cooperation” between Ukraine and international forces.

As such, the site is a powerful symbol of Russia’s longstanding concerns that the 30-member Western military alliance poses a threat to Moscow by operating so close to its territory.

NATO denies it poses a threat, but Russia has repeatedly called on Ukraine to give up its ambitions to join the alliance as a precondition for ending the war.

Lviv Governor Maksym Kozytskyi said most of the Russian missiles fired on Sunday “were shot down because the air defense system was working.” Those who passed killed at least 35 people and injured 134, he said.

A Ukrainian soldier guards his position in Mariupol (Mstyslav Chernov/AP)

Russian fighters also fired at the airport in the western city of Ivano-Frankivsk, located less than 150 km north of Romania and 250 km from Hungary, also NATO allies.

NATO said on Sunday it currently has no personnel in Ukraine, although the United States has increased the number of American troops deployed in Poland.

White House national security adviser Jake Sullivan said the West would react if Russian armaments flow out of Ukraine and hit NATO members, even accidentally.

Mr. Biden “has been clear, repeatedly, that the United States will work with our allies to defend every inch of NATO territory and that means every inch,” Mr. Sullivan told CBS News.

A woman walks past a bomb-damaged building in Kharkiv (Andrew Marienko/AP)

Sullivan will travel to Rome on Monday to meet with senior China foreign policy adviser Yang Jiechi. Their talks will focus on “efforts to manage competition between our two countries and discuss the impact of Russia’s war against Ukraine on regional and global security,” said Emily Horne, on behalf of the security council National White House.

So far, Lviv itself has been spared the scale of the destruction unfolding to the east and south. The city’s population of 721,000 grew during the war, with residents fleeing bombed-out population centers and serving as staging posts for the nearly 2.6 million people who fled the country.

Ukrainian and European leaders have pushed with limited success on Russia to grant safe passage to civilians trapped in the fighting, although Ukrainian President Volodymyr Zelensky said authorities had managed to evacuate nearly 125,000 people from combat zones .

Ukrainian authorities said more than 10 humanitarian corridors would open on Sunday, with Russia’s agreement, including from the battered and besieged port city of Mariupol, where the city council said 2,187 people had been killed.

An injured woman is carried on a stretcher to a local hospital in Novoiavorisk (Bernat Armangue/AP)

The suffering in the port city is “simply immense”, the International Committee of the Red Cross said on Sunday, noting that hundreds of thousands of its residents were “facing extreme or complete shortages of basic necessities such as food, water and medicine”.

Mr Zelensky said in a video address that a convoy carrying 100 tons of humanitarian aid was heading for the town, the capture of which could help Russia establish a land corridor to Crimea, which it seized at the Ukraine in 2014.

Meanwhile, continued fighting on multiple fronts deepened misery in the country on Sunday and sparked renewed international outrage.

In the city of Mykolaiv in southern Ukraine, near the Black Sea, authorities reported that nine people had been killed in bomb attacks.

Meanwhile, they said Russian airstrikes on a monastery and children’s resort in the eastern region of Donetsk hit places where monks and others had taken refuge, injuring 32 people.

Anna, an English teacher from Nova Kakhovka occupied by Russian troops, sits in an underground wagon used as a bomb shelter in Kiev (Efrem Lukatsky/AP)

Around the capital, Kiev, a major political and strategic target of the invasion, fighting has also intensified, with nighttime shelling in the northwestern suburbs and a missile strike on Sunday that destroyed a warehouse to the east.

Kiev region police said on their official website that Russian troops opened fire on a car carrying two American journalists. The force said Brent Renaud died and Juan Arredondo was injured.

Chief regional administrator Oleksiy Kuleba said Russian forces appeared to be trying to blockade and cripple the capital by shelling suburbs day and night.

He vowed that any all-out assault would meet fierce resistance, saying, “We are preparing to defend Kiev, and we are ready to fight for ourselves.”

A woman and two children, who fled Ukraine, rest in the hall of a train station in Przemysl in Poland (Daniel Cole/AP)

Mr Zelensky also alleged that the Russians were using blackmail and bribery to try to force local officials in the southern Kherson region to form a “pseudo-republic” like those in the two eastern regions where Russian-backed separatists have began fighting Ukrainian forces in 2014.

Mr Zelensky reported on Saturday that 1,300 Ukrainian soldiers had died in the war.

The Russians said a few days ago that several hundred of their forces were dead but did not give an updated recent count.

The war repeatedly raised the specter of nuclear accidents, as fighting took place around nuclear power plants.

On Sunday, Ukraine said it had restored a broken power line to the decommissioned Chernobyl power plant, scene of the world’s worst nuclear disaster in 1986.

The plant was cut off from the grid last week and was dependent on generators. This has raised concerns about its ability to keep spent fuel cool, although the International Atomic Energy Agency has played down such concerns.