The US has secretly delivered long-range ballistic missiles to Ukraine to be used against Russian forces, the Pentagon has confirmed, while President Joe Biden alleged that China, Iran and North Korea were supplying weapons and technology to Moscow to boost its military.

President Biden secretly approved the transfer of the long-range ATACMS missiles in February for use inside Ukrainian territory. The ATACMS missiles were then quietly included in the USD 300 million aid package announced on March 12 and ultimately delivered to Ukraine earlier this month, according to Pentagon spokesman Lt. Col. Garron Garn said on Wednesday.

“It was not announced that we are providing Ukraine with this new capability at the time to maintain operational security for Ukraine at their request,” Garn said, deferring questions about their use to Ukraine’s military.

The US previously supplied Ukraine with a mid-range version of the Army Tactical Missile Systems (ATACMS) but had been reluctant to send anything more powerful, partly over concerns about compromising US military readiness.

The ballistic missiles have a range of up to 300 kilometres, nearly doubling the striking distance of Ukraine’s missiles.

President Biden directed his team to take this step following Russia’s procurement and use of North Korean ballistic missiles against Ukraine, according to US media outlets.

Ukrainian officials have been urging the US for the long-range missiles to target deeper behind Russian lines. American officials have previously resisted, citing supply issues and concerns about further provoking Russia if they are deployed.

Speaking from the White House on Wednesday after signing into law a USD 61 billion aid package providing crucial military assistance to Ukraine, Biden said it was a “good day for America, a good day for Ukraine and a good day for world peace.” Over two years, Russia has been responsible for a brutal campaign against Ukraine, he said.

"(Russian President Vladimir) Putin's friends keeping him well supplied. Iran sent him drones. North Korea has sent him ballistic missiles and artillery shells. China is providing components and know-how to boost Russia's defence production," Biden said.

Biden on Wednesday signed the National Security Supplemental USD 95.3 billion aid package to Ukraine and Israel and to strengthen the security of America and its allies in the Indo-Pacific, including Taiwan.

"With all this support, Russia has ramped up its airstrikes against Ukrainian cities and critical infrastructure, rained down munitions on brave Ukrainians defending their homeland. And now, America is going to send Ukraine the supplies they need to keep them in the fight," Biden said on the aid package which was passed by Congress after months of negotiations and debate.

Hours later, the United States started shipping and airlifting equipment to Ukraine for air defence munitions, artillery, rocket systems and armoured vehicles. "This package is literally an investment not only in Ukraine's security but in Europe's security, in our own security," Biden said.

Secretary of State Antony Blinken also announced a new package of weapons and equipment for Ukraine.

"This package, which is valued at up to USD 1 billion, includes urgently needed capabilities, including air defence missiles, munitions for HIMARS, artillery rounds, armoured vehicles, precision aerial munitions, anti-armour weapons, and small arms, equipment and spare parts to help Ukraine defend its territory and protect its people," he said.

"We are sending a powerful message today about the power of American leadership as we support Ukraine's fight against Russian aggression. The United States will continue to work with the coalition of more than 50 countries we have assembled to provide critical support for Ukraine's forces," Blinken said in a statement.

The Pentagon said this package will surge munitions, weapons and equipment forward to support Ukraine's ability to defend its frontlines, protect its cities and counter Russia's continued attacks.

"With the bipartisan support of Congress, Ukraine can count on strong and resolute US leadership to provide consistent security assistance support -- together with some 50 allies and partners -- to ensure its brave defenders receive the critical capabilities needed to fight Russian aggression," the Pentagon said.

Biden warned that if Putin triumphs in Ukraine, the next move of Russian forces could very well be a direct attack on a NATO ally.

"You all know full well that invoking article five of the North Atlantic Treaty would be the first thing that comes to mind, which declares an attack on one as an attack on all. If Putin attacks a NATO ally like he is attacking Ukraine today, we would have no choice but to come to their aid, just like our NATO allies came to our aid after the September 11 (2001) attacks here," he said.

"That is why we are supporting and surging support now to Ukraine to stop Putin from drawing the United States into a war in Europe and in the future. You know, it seems to me, we should take a little bit of a step back and realise what a critical moment this was for the United States and for NATO. This is a historical moment," Biden said.

Ukrainian President Volodymyr Zelenskyy, in an interview with Fox News, thanked the US for sending much-needed military aid amounting to USD 61 billion.

"The moment when we waited for this six-month decision, 61 billion hopes. So I am thankful to the people of America.... And I hope that you and the Americans will feel the result of their help, a resolve to save Ukraine and Ukrainians," he said.

Except for the headline, this story has not been edited by The Telegraph Online staff and has been published from a syndicated feed.