The supplies of the "high-grade military equipment" are worth £100 million ($130 million, 120 million euros), Johnson said.

The attack at Kramatorsk "shows the depths to which (Vladimir) Putin's once-vaunted army has sunk", he told reporters alongside German Chancellor Olaf Scholz, who said the Russian strike was "atrocious".

Scholz also defended Germany against criticism that it is dragging its feet on ending Russian energy imports as part of Western sanctions over Putin's invasion of Ukraine.

"We are doing all we can and we are doing a lot," the chancellor said, pointing to Germany's long-term diversification to alternative energy and other suppliers for natural gas.

After talks with Scholz in Downing Street, Johnson said Britain and Germany would work together on renewable technologies.

"We cannot transform our energy systems overnight, but we also know that Putin's war will not end overnight," the prime minister said.