The US on Friday announced a $400 million military aid package for Ukraine, as Kyiv tries to stop advances by Russian troops in the Kharkiv region.
White House national security spokesman John Kirby said President Joe Biden's administration has been working to get Ukraine the weapons systems that it needs to defend itself against Russia's intensified attacks.
“We are confident in the Ukrainian armed forces and we are working around the clock to get them the equipment, the tools and the weapons that they need to defend against these attacks,” Mr Kirby said.
“No one should underestimate the Ukrainian people and no one should underestimate President Biden's commitment and resolve to standing with Ukraine.”
Mr Kirby said it is likely that Russia will increase the intensity of its attacks over the coming weeks and send additional troops to the north-eastern region of Kharkiv in an attempt to establish a shallow buffer zone along the Ukrainian border.
But the US does not expect any major breakthroughs, he added.
The latest tranche of aid, Mr Kirby said, includes additional artillery ammunition, interceptors and anti-aircraft missiles, armoured vehicles, artillery rounds, anti-armour systems and other weapons and equipment.
In late April, the US Congress passed a supplemental funding that included $60 billion in aid for Ukraine.
Mr Biden announced $1 billion in weapons through his drawdown authority. Days later, the Pentagon announced a $6 billion military package, its biggest yet for Kyiv.
Ukraine-Russia conflict latest – in pictures
Ukrainian rescuers at the site of a rocket attack on a residential building in Dnipro, south-eastern Ukraine. EPA
Rescues carry a person wounded by a Russian missile strike in Dnipro. Reuters
Rescuers tackle a blaze at a building struck by Russian bombs, in Dnipro. AP
An apartment building hit by a Russian missile strike in Dnipro. Reuters
Ukrainian soldiers fire at Russian positions near the town of Kupyansk, Kharkiv Region. AFP
A building destroyed by a Russian air strike in the front-line town of Orikhiv. AP
A dog stands on the rubble as rescuers work at the site of a destroyed building during a Russian missile strike in Chernihiv. Reuters
A Ukrainian serviceman works on an FPV drone in a workshop in the Donetsk region. Reuters
Local resident Kateryna, 77-years-old, walks with a litter of puppies, which she feeds in the yard of her bomb-damaged apartment block in the town of Kurakhove. AFP
Ukrainian rescuers at the scene of a missile strike near a residential building, in Zaporizhzhia. EPA
A woman looks at the damage in her flat after debris from a missile strike hit nearby, in Kyiv. EPA
Ukrainian firefighters at the scene of a missile strike in Kyiv. EPA
Ukrainian servicemen take part in military training at an undisclosed location near the frontline. EPA
Ukrainian troops run near the site of a rocket attack on an industrial building, in Kharkiv. EPA
A pilot operates a drone at a training ground in the Kyiv region. AFP
Ukrainian and Russian soldiers are depicted in a tug-of-war on a memorial in Izium, Kharkiv region. AP
A man looks at his home in a damaged apartment building in Izium, Kharkiv. AP
Ukrainian civilian women are trained to use weapons, in Kyiv. AFP
A Ukrainian soldier mans a position as new recruits receive training at an undisclosed location in the Donetsk region. EPA
A man pays tribute at a makeshift memorial for fallen Ukrainian soldiers, at the Independence Square in Kyiv. AFP
An emergency worker at the scene of a Russian attack in Odesa. AP
Ukrainian recruits are trained by members of the Danish military, in the east of England. AP
Danylo, commander of an engineering and sapper company of the Ukrainian Armed Forces, inspects pyramidal anti-tank obstacles known as 'dragon's teeth' before installing them into a new fortification line in Zaporizhzhia region. Reuters