Britain is supplying Ukraine with short-range anti-tank missiles for self-defense after Russia rounded up around 100,000 troops on its border, the defense secretary has said.
Ben Wallace told MPs that a small team of British soldiers would also be sent to Ukraine to provide training.
He said there was “legitimate and real cause for concern” that Russian troops could be used for an invasion.
Russia denies any invasion plan and accuses the West of aggression.
Dozens of British soldiers have been in Ukraine since 2015 to help train their armed forces, and the UK has also pledged to help rebuild Ukraine’s navy after Russia invaded Crimea in 2014.
But Mr Wallace said the UK would provide further security assistance in light of Russia’s “increasingly threatening behaviour”.
The first batch of small anti-armour weapons was sent on Monday, although the Secretary of Defense did not specify the type.
“Ukraine has every right to defend its borders and this new aid package further strengthens its ability to do so,” he told MPs.
“Let’s be clear: this support is for short-range, clearly defensive weapon capabilities; they are not strategic weapons and pose no threat to Russia; they are to be used in self-defense.”
He said there was “a set of international sanctions ready to be applied” if Russia were to take “destabilizing actions” in Ukraine.
Any invasion would be considered an “occupation” which “could result in enormous loss of life on all sides”, the defense secretary said.
He said: “We want to be friends with the Russian people as we have been for hundreds of years. And there is a world where we can establish a mutually beneficial relationship with Russia.
“I still remain hopeful that diplomacy will prevail. It’s up to President Putin to choose between diplomacy and dialogue, or conflict and its consequences.”
Ukraine’s ambassador to the UK welcomed Britain’s decision to send additional weapons and troops, but told the BBC the biggest problem was that they were not members of NATO.
“We wanted to be in NATO…we are alone against the biggest army in Europe,” said Vadym Prystaiko.
The conflict between Russian-backed separatists in eastern Ukraine and the Ukrainian military has been ongoing since 2014, although a fragile ceasefire is in place.
Western and Ukrainian intelligence have suggested an invasion or incursion could occur in early 2022, after Russian forces have gathered on the border.
Meanwhile, Russia accused NATO countries of “pumping” Ukraine with weapons and said the United States was fueling tensions in the region.
Its main demand is to stop any eastward expansion of NATO, with Deputy Foreign Minister Sergei Ryabkov declaring after recent talks that it is “absolutely obligatory to ensure that Ukraine never becomes , never a member of NATO.