Lithuania, Latvia and Estonia can now send American-made missiles and weapons to Kiev to "help bolster its defences in the face of growing Russian aggression".
The US State Department has cleared Lithuania, Latvia and Estonia to send US-made missiles and other weapons to Ukraine as President Joe Biden predicted Russia would move in on Ukraine.
The third-party transfer agreements will allow Estonia to transfer Javelin anti-tank missiles to Ukraine, while Lithuania will be permitted to send Stinger missiles, a source familiar with the decision said on Thursday.
A State Department spokesperson confirmed that the US government had approved third-party transfers allowing Estonia, Latvia, Lithuania and Britain to provide US-made equipment from their inventories to Ukraine.
"The United States and its allies and partners are standing together to expedite security assistance to Ukraine," the spokesperson said.
"We are in close touch with our Ukrainian partners and our NATO Allies and are creatively utilising all available security cooperation tools to help Ukraine bolster its defences in the face of growing Russian aggression."
They gave no details on which weapons would be sent.
READ MORE: US warns Russia could attack Ukraine 'at any point'
Standing with Ukraine
News about the approved weapons transfers emerged late on Wednesday after Biden told a news conference that Russia would pay dearly if it invaded Ukraine.
The spokesperson said the Biden administration approved $200 million in additional defensive security assistance to Ukraine in December, along with $60 billion in equipment from existing US military stocks.
US officials were also identifying additional equipment that could be delivered from excess US military stocks.
"As President Biden told President Putin, should Russia further invade Ukraine, we will provide additional defensive material to the Ukrainians," the spokesperson said.
"We are committed to Ukraine’s sovereignty and territorial integrity and will continue to provide Ukraine the support it needs."
READ MORE: US announces fresh military aid to Ukraine amid Russia invasion fears
Meanwhile, US Secretary of State Antony Blinken arrived in Berlin for meetings with key European allies on Thursday, as part of a whirlwind diplomatic tour to stop Russia from marching on Ukraine.
Blinken will seek a united front with counterparts from France and Germany as well as Britain's junior foreign minister before his crunch talks with Russia's Sergey Lavrov on Friday.
Russian officials have repeatedly denied planning to invade Ukraine, but the Kremlin has massed over 100,000 troops near Ukraine's borders, a move that the West interprets as preparation for an invasion.
READ MORE: What does Russia hope to achieve with its escalation in Ukraine?