LONDON — British Prime Minister Andy Burnham said Monday that the U.K. will help Ukraine make its own long-range missiles by sharing classified technical information for British components.

Burnham, who was in Kyiv alongside other international leaders for Ukraine’s Independence Day, said defense firm MBDA will release details on U.K.-made parts for the SCALP missile to Ukraine to help the country assemble the weapons.

Here’s what to know about the missiles and how significant the announcement is for Ukraine:

The SCALP missile is the French-produced version of the U.K.’s Storm Shadow, an air-launched, high-precision missile with a range of more than 250 kilometers (155 miles). Both use shared French and British technology.

Measuring 5.1 meters (16.7 feet,) the missile is hard to detect and is designed to hit fixed or stationary targets such as hardened bunkers and key infrastructure, according to MBDA. The defense firm says the missile uses an advanced navigation system and is exceptionally accurate.

Storm Shadow and SCALP missiles are in service with the British, French and Italian air forces, as well as other export countries. They have been used in conflicts in Iraq, Libya and Syria.

Ukraine is already in talks with France to work toward assembly lines for the missiles in Ukraine so that Kyiv can produce its own version of the weapons. It is not known how far advanced the plans are, or when such missiles may start benefitting Ukraine in its war against Russia.

Douglas Barrie, a senior fellow at the International Institute for Strategic Studies, said that while the U.K.’s decision to share classified information was notable, much depends on the pace at which local assembly can be established.

“Any impact … will in part depend on how quickly Ukrainian-assembled SCALP cruise missiles can be introduced into service,” he said.

The news will not help Ukraine in the short term as it struggles to secure more Patriot interceptor missiles.

Ukrainian President Volodymyr Zelenskyy said on Sunday that his country is receiving substantially fewer of those missiles, even as Russian ballistic attacks are increasing. The shortfall is particularly serious because the United States and European partners are struggling to expand production.

Still, the British announcement on Monday drew ire from Russia. Kremlin spokesman Dmitry Peskov accused the U.K. of “fanning the flame” of the war on Kyiv’s side — a claim Burnham swiftly dismissed.

“Who started the fire?” he asked reporters when asked about the comments on Monday.

Britain became the first country to supply longer-range strike weapons to Ukraine in 2023 when it donated a number of Storm Shadow missiles to Kyiv. The missiles gave Ukraine capacity to strike targets in Russia well behind the front lines, as well as in Russian-occupied Crimea.

The U.K. is also helping Ukraine develop low-cost strike weapons in other ways.

Officials have been working with British defense companies to test a new ground-launched strike system that could hit targets more than 500 kilometers (310 miles) away while carrying a powerful 225-kilogram (496-pound) warhead.