FACTBOX-Shifting red lines in West's support for Ukraine now allows strikes deep into Russia

The United States will allow Ukraine to use U.S.-made weapons such as ATACMS rockets, which have a range of up to 190 miles (306 km), to strike deep into Russia, two U.S. officials and a source familiar with the decision said on Sunday.

The reversal of policy, nearly 1,000 days since Russia started its full-scale invasion on Ukraine, comes largely in response to Russia's deployment of North Korean troops to supplement its forces, a development that has caused alarm in Washington and Kyiv, a U.S. official and a source familiar with the decision told Reuters.

There was no immediate response from the Kremlin, but some Russian senior lawmakers said loosening of the limits on Ukraine's use of U.S. weapons is a major escalation.

President Vladimir Putin said in September that the step would mean "direct involvement of NATO countries" in the war.

Below is a list of some of the weapons systems Western countries were initially hesitant to give Ukraine but which were eventually handed over.

ATACMS

Ukraine's President Volodymyr Zelenskiy has been long asking Kyiv's allies to give it the capability to strike deeper behind Russian lines, a crucial part of disrupting enemy logistics and command chains.

The U.S. held off on supplying Army Tactical Missile Systems (ATACMS) - because of concerns that Russia would see this as escalatory - until October 2023, when they supplied a short-range version with a maximum range of 165 km (100 miles).

This was followed up by deliveries in early 2024 of a longer-range version of the ATACMS missile which has a range of up to 300 km (165 miles).

With the U.S. permission, Ukraine will now be able to strike targets deep inside Russia, most likely around Russia's Kursk region, where Kyiv forces still hold swaths of the territory and where North Korean troops are reported to be concentrated.

In August, analysts at the Washington-based Institute for the Study of War said that hundreds of known Russian military objects were in the range of ATACMS.

It is likely, however, that some of the military assets, despite the logistical difficulties, have been moved deeper into Russia in anticipation of the U.S. decision.

F-16s

Ukraine asked for F-16 fighter jets from soon after start of the invasion to boost its long-range strike ability as well as to use the jets to shoot down the volleys of cruise missiles fired deep into Ukraine by Moscow.

Ukrainian pilots started to be trained on the jets only in August 2023, after lengthy negotiations between the coalition of allies who would provide planes or training.

Ukraine was keen to finish the training process as soon as possible, and the confirmation that Ukraine had received the first planes came on July 31 this year.

Since then, one of the planes has crashed while attempting to engage Russian missiles fired at land targets in Ukraine.

WESTERN TANKS

Although Ukraine's eastern European allies provided it with Soviet-era tanks at the start of the invasion, Kyiv coveted Western-built tanks, such as Britain's Challenger 2 and the German-built Leopard 2, until their transfer was approved after a lengthy negotiation in January 2023.

The agreement on a coalition of countries to supply the tanks was delayed by concerns in Germany that the move could be seen as escalatory by Russia. Berlin eventually approved the transfer of Leopard 2 tanks from other countries' stockpiles as well as its own.

STRIKES ON RUSSIA

For over two years, the United States did not allow Ukraine to strike Russia with any of its weapons systems.

After a Russian assault in May 2024 near the northwestern city of Kharkiv, Washington changed its stance under pressure from Kyiv.

Ukraine was secretly authorised by President Joe Biden to fire U.S.-supplied weapons at military targets inside Russia that were supporting the Kharkiv offensive.