The new pledge nearly doubles Britain's previous spending commitments to Kiev

The UK pledged a further Pound 1.3 billion ($1.6 billion) in military support and aid to Ukraine on Saturday. London said the move nearly doubles London's previous spending commitments to Kiev, and is the country's highest rate of spending on a conflict since the wars in Iraq and Afghanistan.

"Putin's brutal attack is not only causing untold devastation in Ukraine - it is also threatening peace and security across Europe," Prime Minister Boris Johnston said in a statement, as quoted by Reuters.

The extra money will come from a reserve used by the government for emergencies. Like other NATO member states, the UK has been increasingly supplying Kiev with weapons, including anti-tank and anti-aircraft missile systems and armored vehicles.

This week, London said it was sending 13 armored vehicles to Ukrainian police and the National Guard. The UK government has also been delivering tanks to Poland in order to replace those Warsaw has donated to Kiev.

Similarly, the US pledged an additional $150 million in military assistance to Ukraine on Friday. The package includes 25,000 155mm artillery rounds, as well as radars and electronic jamming equipment.

Russia has repeatedly criticized the West for "flooding" Ukraine with weapons, and warned in April that foreign arms become legitimate targets once they reach Ukrainian soil.

Russia attacked its neighboring state in late February, following Ukraine's failure to implement the terms of the Minsk agreements, first signed in 2014, and Moscow's eventual recognition of the Donbass republics of Donetsk and Lugansk. The German- and French-brokered protocols were designed to give the breakaway regions special status within the Ukrainian state.

The Kremlin has since demanded that Ukraine officially declare itself a neutral country that will never join the US-led NATO military bloc. Kiev insists the Russian offensive was completely unprovoked and has denied claims it was planning to retake the two republics by force.