Britain has delivered more Storm Shadow cruise missiles to Ukraine, giving Ukrainian forces a new long-range strike capability ahead of a long-awaited counteroffensive against Russian forces, several senior Western officials told CNN.

The Storm Shadow is a long-range stealth-capable cruise missile jointly developed by the UK and France that is normally air-launched.

It has a range of more than 250 km, which is slightly less than the 300 km of the US Army’s surface-to-surface tactical missile systems (ATACMS), which Ukraine has long demanded.

Storm Shadow has the range necessary to strike Russian-controlled territories in eastern Ukraine.

A Western official told CNN that Britain had received assurances from the Ukrainian government that the missiles would only be used to attack Ukrainian sovereign territory and not inside Russia.

The information appeared after last week a group of European countries led by Great Britain turned to companies with a proposal to supply Ukraine with missiles with a range of up to 300 km.