"Himars have arrived to Ukraine. Thank you to my colleague and friend @SecDef Lloyd J. Austin III for these powerful tools! Summer will be hot for russian occupiers. And the last one for some of them," Ukraine Defence Minister Oleksiy Reznikov wrote on Twitter.

The United States and NATO partners are sending Ukraine heavy armament, such as howitzers and Himars rocket artillery -- the latter offering greater range and precision than that offered by the Russian equivalent.

While the West has sent weapons into Ukraine to help it fight the Kremlin's forces, Kyiv complains it has only received a fraction of what it needs and is clamouring for heavier weaponry.