LONDON >> British weapons can be used by Ukrainian forces in operations on Russian territory, Britain’s Ministry of Defence said on Thursday, but restrictions on the use of long-range Storm Shadow missiles remain.

In the last two weeks, Ukraine has carried out the biggest foreign attack on sovereign Russian territory since World War Two, which one Ukrainian official has said is designed to create a buffer zone to protect its population against attack.

Britain’s then foreign minister David Cameron said in May that Ukraine had a right to use weapons provided by London to strike targets inside Russia, but the government had not commented before on Ukraine’s use of the donated weapons by ground forces on Russian territory.

Setting out the use of weapons deliveries in some of the most explicit terms to date, a spokesperson for Britain’s Ministry of Defence said that Ukraine had a “clear right of self-defense against Russia’s illegal attacks” and “that does not preclude operations inside Russia”.

“We make clear during the gifting process that equipment is to be used in line with international law,” the spokesperson said.

The policy means that British tanks, anti-tank missiles, and other military equipment given to Ukraine can be used inside Russia as part of Ukraine’s defense against Russia’s invasion.

Restrictions on the use of British-supplied long-range Storm Shadow missiles, which can only be used within Ukraine’s internationally accepted borders, remain in place.

Using swarms of drones, heavy artillery and tanks, Ukraine says it has captured more than 1,000 square 390 square miles of Russian territory since Aug. 6 in a move that Russian leader Vladimir Putin called a “major provocation”.

A British source said Ukrainian troops are thought to have used British Challenger 2 tanks inside Russia.

The Ministry of Defence declined to comment on the use of British tanks inside Russia.

Britain has pledged 7.6 billion pounds ($9.77 billion) in military assistance for Ukraine since February 2022 when the Russian invasion began, according to the House of Commons library, which publishes research.

This includes 14 of Britain’s main battle tanks last year along with armored vehicles, ammunition, air defense systems, electronic warfare equipment and artillery.

But Britain, like other Western governments, has so far refused to allow Ukraine to use long-range weapons because of the perceived risk of escalation in the conflict.

Russia has said it would respond if Britain allowed Ukraine to strike Russia with British weapons.

Ukrainian President Volodymyr Zelenskiy again this week urged Western allies to permit long-range missile strikes into Russia.