Russian paratroopers land in Ukraine's second largest city

Ukraine's military has confirmed earlier reports that Russian paratroopers have landed in Kharkiv in an effort to take the besieged city.

According to the Ukrainian military, the aerial assault began just as air raid sirens were starting to sound in Kharkiv and the surrounding region.

The statement adds that the Russian troops attacked a regional military hospital, and that fighting is ongoing.

Kharkiv Region Police Chief Volodymyr Tymoshko told reporters this evening (NZ time) that no Ukrainian troops were killed in the gun battle.

"Currently the situation near the hospital is under control, security has been strengthened," he said, according to Ukrainian media.

Kharkiv has been the epicentre of much of the violence seen in Ukraine in recent days.

It is a predominantly Russian-speaking city of 1.5 million people.

On Tuesday, a missile struck the local government headquarters of Ukraine's second-largest city around 8am local time, sending a massive fireball into the sky and burning cars and nearby buildings.

Another strike occurred later on Tuesday in one of Kharkiv's residential neighborhoods. Ukrainian President Volodymyr Zelensky later called the attack a war crime.

At least 21 people were killed and 112 wounded in shelling in Kharkiv in the last 24 hours, regional governor Oleg Synegubov said on Wednesday.

More than 450,000 people have fled Ukraine to Poland, and a further 113,000 to Romania.

Some pundits have speculated that the artillery strikes on residential communities could be an effort by Russia to weaken the Ukrainian resolve to fight.

US will close air space to Russian planes

The United States closed its airspace to Russian planes as the Russian military attempted to encircle and subdue Ukrainian cities with intensifying bombardments on Wednesday, seven days into an invasion that has sparked massive international sanctions.

Already shunned by the West, Russia has shown no sign of stopping an assault that has included strikes on Kyiv and rocket attacks in the second city of Kharkiv. Dozens have been killed.

Russia has failed to capture a single city since its full-scale invasion began nearly a week ago, and Western analysts say Moscow has fallen back on tactics which call for devastating shelling of built-up areas before entering them.

Hundreds of thousands of Ukrainians have fled the fighting as a kilometres-long Russian military convoy north of Kyiv readies to advance on the city. West of Kyiv, in the city of Zhytomyr, four people, including a child, were killed on Tuesday by a Russian cruise missile, a Ukrainian official said.

Ukrainian President Zelensky called on Russia to stop bombarding civilians and resume talks.

"It's necessary to at least stop bombing people, just stop the bombing and then sit down at the negotiating table," he told Reuters and CNN in a joint interview in a heavily guarded government compound in Kyiv.

US President Joe Biden vowed Russian President Vladimir Putin would pay a heavy price for his decision to invade Ukraine, a Western-leaning democratic country of 44 million people.

"He has no idea what's coming," he said in a State of the Union address in the chamber of the House of Representatives.

The lawmakers stood, applauded and roared, many of them waving Ukrainian flags and wearing the country's blue and yellow colours.

Biden announced a further ratcheting up of sanctions on Moscow, joining the European Union and Canada in banning Russian planes from US airspace. He also said the Justice Department would seek to seize the yachts, luxury apartments and private jets of wealthy Russians with ties to Putin.

The Russian leader ordered a "special military operation" last Thursday in a bid to disarm Ukraine, capture the "neo-Nazis" he says are running the country and crush its hopes of closer ties to the West.

'Freeze and seize'

Ukraine, which is not a member of NATO, has called on the US-led military alliance to implement a no-fly zone - a request rejected by Washington, which fears stoking a direct conflict between the world's two biggest nuclear powers.

Washington and its allies have instead sent weapons to Kyiv, and Treasury Secretary Janet Yellen said the United States had agreed with partners to convene a task force "to freeze and seize the assets of key Russian elites".

The move "will inflict financial pain on the powerful individuals surrounding Putin and make clear that no one is beyond our collective reach," Yellen said in a statement following a Tuesday call with Group of Seven officials.

The West is shutting off Russia's economy from the global financial system, pushing international companies to halt sales, cut ties, and dump tens of billions of dollars' worth of investments.

Exxon Mobil joined other major Western energy companies including British BP and Shell in announcing it would quit oil-rich Russia over the invasion.

Apple stopped sales of iPhones and other products in Russia, and was making changes to its Maps app to protect civilians in Ukraine. Alphabet's Google dropped Russian state publishers from its news, and Ford Motors suspended operations in the country.

Russia on Tuesday placed temporary restrictions on foreigners seeking to exit Russia assets, meaning that billions of dollars worth of securities held by foreigners are at risk of being trapped.

Its military move on Kyiv has stalled as its forces struggle with shortages of food and fuel, and some units appeared to have low morale, a senior US defence official said on Tuesday.

The United Nations says at least 136 civilians have been killed in the invasion, but that the real number of people is likely much higher.

Ukraine's air force continued to defy expectations that Russia would achieve swift dominance of the air.

"The airspace is actively contested every day," a senior US defence official said, speaking on condition of anonymity.

- BBC / Reuters