(NewsNation) — The U.S. and allied countries have a sent a dizzying array of weaponry to Ukraine to help it defend against the Russian incursion, but Ukrainian President Volodymyr Zelenskyy is meeting reluctance to fulfill one of his major requests: long-range missiles.

While Ukraine has received plenty of anti-tank and anti-aircraft missiles and other weapons, the NATO allies have thus far been unwilling to send any sort of long-range missiles that could be used to strike targets inside Russia for fear these could be seen as crossing the line from defense to aggression.

Specifically, what Ukraine has has asked for is the M270 MLRS (Multiple launch rocket system), which can fire up to 180 miles, easily striking targets within Russia. This is far different from the M777 howitzers that have been sent in abundance which allow Ukrainian forces to fend off Russian attacks with precision shells.

For the time being, Ukraine will have to be content with receiving what are perceived to be defensive weapons, and given the Russian offensive in the Donbas and its recent increase, the more of those the country receives the better off it will be.