Russia says US plans to supply Ukraine with its most powerful rocket systems yet is “adding fuel to the fire deliberately” and could draw America into the war.

After initially fearing Russian provocation, the US has agreed to arm Ukraine with rockets that can strike with precision at long-range Russian targets as part of a new package.

Although late in the conflict, the advanced weapons would enable Ukraine to match Russia’s long-range artillery which has devastated its east.

Russia has called the move a “direct provocation” and said it was aimed at drawing the west into the conflict which has been waging for three months now.

Kremlin spokesperson Dmitry Peskov told reporters: “We believe that the United States is purposefully and diligently adding fuel to the fire.”

He told a news conference in Saudi Arabia: “It is a direct provocation (by Ukraine), aimed at involving the West in military action.”

Russian Foreign Minister Sergei Lavrov said Kyiv’s “demands” from its Western patrons “overstep all bounds of decency and diplomatic relations and, secondly, are a direct provocation aimed at drawing the West into combat”.

Washington agreed to supply the rockets, which are capable of hitting targets as far away as 80 km, after Ukraine gave “assurances” it would not use the missiles to strike inside Russia itself, senior US officials said.

Mr Peskov said Moscow did not trust such assurances. He said it was assessing the risk of rockets being fired into Russian territory and was taking appropriate measures, but that it viewed Washington’s step “extremely negatively.”

When asked how Russia would respond if Ukraine used US-supplied rockets to strike Russian territory, Mr Peskov said: “Let’s not talk about worst-case scenarios”.

He added that such supplies would not encourage Ukraine’s leadership to resume stalled peace talks.

Ukrainian officials have been asking allies for longer-range missile systems that can fire a barrage of rockets hundreds of miles away, in the hopes of turning the tide of the war.

US President Joe Biden wrote in an opinion piece in the New York Times: “We have moved quickly to send Ukraine a significant amount of weaponry and ammunition so that it can fight on the battlefield and be in the strongest possible position at the negotiating table.”

Shortly after the US decision was announced, the Russian defence ministry said Russia’s nuclear forces were holding drills in the Ivanovo province, northeast of Moscow, the Interfax news agency reported.

Some 1000 servicemen were exercising in intense manoeuvres using more than 100 vehicles including Yars intercontinental ballistic missile launchers, it cited the ministry as saying.

There was no mention of the US decision to supply new weapons in the Interfax report.

Russia has also completed testing of its hypersonic Zircon cruise missile and will deploy it by the end of the year on a new frigate of its Northern Fleet, a senior military officer said on Wednesday.

Russia pounds symbolic city

People from Severodonetsk are evacuated from the besieged city. Photo: Getty

Russian troops have pressed closer to the centre of a factory city in their drive to grab a swathe of eastern Ukraine.

Ukraine’s General Staff on Wednesday said Russian forces were pounding infrastructure in eastern and southern regions including the symbolically important industrial city of Sievierodonetsk, which they entered on May 27.

It has been the main focus of their ground offensive for several weeks.

Sievierodonetsk is a Soviet-era city that houses a large chemical factory. According to the local governor, a Russian airstrike hit a large chemical plant in the city on Tuesday, blowing up a tank of toxic nitric acid.

Russia “attacked the Azot factory from a plane, resulting on the release of toxic substances,” Governor Serhiy Gaidai said, urging residents to remain inside. Reuters could not independently confirm the cause of the incident.

Ukraine’s General Staff said Russian forces continued to pound northern, southern and eastern districts of Sievierodonetsk.

If Russia captures the city and its smaller twin Lysychansk on the west bank of the Siverskyi Donets river, it will hold all of Luhansk, one of two provinces in the eastern Donbas region that Moscow claims on behalf of separatists and a key war aim of President Vladimir Putin.

-with AAP