The invasion of Ukraine has taken a particularly heartbreaking turn after a children's and maternity hospital in Mariupol was bombed by Russian forces. 

Children were reportedly trapped beneath the rubble, sparking desperate rescue attempts. 

Ukrainian officials said the attack wounded at least 17 people. 

The ground shook more than a mile away when the Mariupol complex was hit by a series of blasts that blew out windows and ripped away much of the front of one building. Police and soldiers rushed to the scene to evacuate victims, carrying out a heavily pregnant and bleeding woman on a stretcher as light snow drifted down on burning and mangled cars and trees shattered by the blast. 

An injured pregnant woman walks downstairs in the maternity hospital damaged by shelling in Mariupol, Ukraine, yesterday. Photo / AP 

Another woman wailed as she clutched her child. In the courtyard, a blast crater extended at least two stories deep. 

"Today Russia committed a huge crime," said Volodymir Nikulin, a top regional police official, standing in the ruins. "It is a war crime without any justification." 

Meanwhile, fears are growing over a potential radiation leak after power to the Chernobyl nuclear plant was cut, and Russia has also reportedly confirmed the use of lethal thermobaric weapons in Ukraine. 

Today's live updates of the war in Ukraine continues below. 

US citizens seek to join foreign fighters in Ukraine 

Russia's invasion of Ukraine has given the smaller nation's embassy in Washington an unexpected role: recruitment center for Americans who want to join the fight. 

Diplomats working out of the embassy, in a townhouse in the Georgetown section of the city, are fielding thousands of offers from volunteers seeking to fight for Ukraine, even as they work on the far more pressing matter of securing weapons to defend against an increasingly brutal Russian onslaught. 

"They really feel that this war is unfair, unprovoked," said Ukraine's military attaché, Maj. Gen. Borys Kremenetskyi. "They feel that they have to go and help." 

U.S. volunteers represent just a small subset of foreigners seeking to fight for Ukraine, who in turn comprise just a tiny fraction of the international assistance that has flowed into the country. Still, it is a a reflection of the passion, supercharged in an era of social media, that the attack and the mounting civilian casualties have stirred. 

"This is not mercenaries who are coming to earn money," Kremenetskyi said. "This is people of goodwill who are coming to assist Ukraine to fight for freedom." 

West's 'serious concerns' over chemical weapons 

Officials abroad remain on edge over the possibility of an "utterly horrific" attack on the capital of Kyiv as Russian forces face ongoing setbacks two weeks into their Ukraine campaign. 

"I think we've got good reason to be concerned about possible use of non-conventional weapons, partly because of what we've seen has happened in other theatres," one official told the UK Telegraph. 

"As I've mentioned before, for example, what we've seen in Syria, partly because we've seen a bit of setting the scene for that in the false flag claims that are coming out, and other indications as well." 

The development came after Russia's Foreign Ministry Spokeswoman Maria Zakharova said evidence Ukraine had been "concealing traces of a military biological programme implemented with funding from the United States" had been uncovered. 

On Wednesday, Britain's Ministry of Defence said there had been a notable "intensification of Russian accusations that Ukraine is developing nuclear or biological weapons" since late February. 

"These narratives are long standing but are currently likely being amplified as part of a retrospective justification for Russia's invasion of Ukraine," she said. 

US House of Representatives approves $13.6b for Ukraine in huge spending bill 

The House approved a massive spending bill Wednesday night that would rush $13.6 billion in U.S. aid to battered Ukraine and its European allies, after top Democrats were forced to abruptly drop their plan to include fresh funds to battle Covid-19. 

Passage of the Ukraine aid and the $1.5 trillion government-wide legislation that carried it let both parties lay claim to election-year victories for their priorities. Democrats won treasured domestic initiatives, Republicans achieved defense boosts, and both got their imprint on funds to counter Russia's brutal invasion of its western neighbor. Senate approval was assured by week's end or perhaps slightly longer. 

Hours earlier, House Speaker Nancy Pelosi, D-Calif., had to abandon the bill's $15.6 billion for combating the pandemic, a decision she called "heartbreaking" and that spelled defeat for a top priority of President Joe Biden and party leaders. The money was mostly to bolster U.S. supplies of vaccines, treatments and tests and battle the disease around the world, but a Democratic revolt over Republican-demanded state aid cuts to cover the new initiatives' costs forced her to scrap that spending. 

700 evacuate Russia-occupied towns near Kyiv 

Hundreds of Ukrainians living in towns occupied by Russian troops on the outskirts of Kyiv fled Wednesday. 

Streams of cars - some fixed with white flags - filed down the road, joined by lines of yellow buses marked with red crosses. 

The Interior Ministry said about 700 people were evacuated from Vorzel and Irpin. People from three other Kyiv suburbs were unable to leave. Some who managed to get out said they hadn't eaten in days. 

"I forgot when I ate last," said an Irpin resident who gave only her first name, Olena. "I'm so scared. I need to keep walking." 

Iuliia Bushinska, a Vorzel resident, said: "Occupiers came to our house and they were ready to shoot us." 

"They took away our house, our car, they took away our documents. So we need to start our life from the beginning. We survived things that I never experienced in my life," Bushinska said. 

Putin 'angry and frustrated' by Russia's failure 

Russian President Vladimir Putin is reportedly "angry and frustrated" by Ukraine's resistance and the failure of his troops to capture Kyiv. 

That's according to CIA director William Burns, who told America's ABC news that his frustration would likely cause Putin to "double down" attacks against the nation "with no regard for civilian casualties". 

"He has no sustainable political endgame in the face of what is going to continue to be fierce resistance from Ukrainians," Burns said. 

"Putin has commented privately and publicly over the years that he doesn't believe Ukraine's a real country. He's dead wrong about that – real countries fight back. 

"And that's what the Ukrainians have done quite heroically over the last 12 days." 

'Mind-boggling bravery' as bomb defused with bare hands 

The heroic efforts of two Ukrainian men have made global headlines after a video captured them defusing a bomb with nothing but their bare hands and a bottle of water. 

According to Charles Lister, senior fellow and the Director of the Syria and Countering Terrorism & Extremism programs at the Middle East Institute, the bomb was so powerful it could "flatten a building". 

But that didn't stop the Ukrainian explosive ordnance disposal specialists from risking their lives to save others. 

Russian troops' cruel taunt 

Russia's defence ministry has posted a video of troops cruelly taunting Ukraine by waving Soviet Union flags from tanks rolling through the invaded nation. 

It is not known exactly where the act took place, with Russian authorities only revealing that tanks were headed to a "designated area". 

"The Russian Armed Forces units continue to take control of the Ukrainian regions occupied by nationalists within special military operation," the ministry said alongside the video. 

Ukraine gained independence in 1991 during the fall of the Soviet Union after being under Moscow's control for almost seven decades. 

The flag is seen as an inflammatory symbol of that oppression and was likely deliberately brandished to cause further distress to the Ukrainian people. 

It has been interpreted as a threat of the return of the Soviet Union, and has sparked outrage on social media. 

- Additional reporting by news.com.au and AP