Ukraine has fired US-made long-range missiles into Russia for the first time since the Biden administration lifted restrictions on their use, drawing a warning from Moscow that it would respond “accordingly”.

Russia’s defence ministry said Ukraine launched six US-made Atacms missiles targeting the south-western Bryansk region overnight. Ukrainian president Volodomyr Zelenskyy did not directly confirm the Bryansk attack but said: “We now have Atacms, Ukrainian long-range capabilities, and we will use them.”

Russia’s longtime foreign minister, Sergei Lavrov, in Rio de Janeiro for the G20 summit, said the Ukrainian use of Atacms was a clear signal that the west wanted to escalate the conflict. “Without the Americans, it is impossible to use these hi-tech missiles, as Putin has repeatedly said,” Lavrov said.

He said Russia would respond “accordingly” to the attack.

The target appeared to be an ammunition warehouse in Bryansk region, which lies north-west of the Kursk region where a Ukrainian incursion has been under way since early August.

Ukraine’s general staff said in a statement on Facebook that it hit a military arsenal of the 1046th logistics centre outside the city of Karachev without confirming the use of the missiles. Russian independent media reported that residents of Karachev heard explosions overnight.

Several videos circulating online, purportedly from the Karachev district, featured the sound of detonations and visible flashes.

The Russian defence ministry claimed that five of the missiles were shot down and another was damaged. It said debris from the rockets caused a fire at an unnamed military facility.

The reports of an Atacms strike emerged hours after Vladimir Putin signed a revised nuclear doctrine lowering the threshold for using nuclear weapons, as the Kremlin intensified its rhetoric over Biden’s decision to permit Kyiv to use US-made long-range missiles for strikes inside Russia.

Russia’s revised nuclear doctrine declares that a conventional attack on Russia by any nation that is supported by a nuclear power will be considered a joint attack on his country. The doctrine, which outlines the conditions under which Russia’s leadership might consider launching a nuclear strike, also states that an attack using conventional missiles, drones or other aircraft could be seen as justification for a nuclear response.

While Russia has been planning to update its nuclear doctrine for months, the timing of Putin’s signature will be seen as a clear reaction to Biden’s decision to allow Ukraine to conduct strikes with the 190-mile range army tactical missile system, known by the acronym Atacms, deep into sovereign Russian domain.

Shortly after Putin signed the decree, the Kremlin said the purpose of the updated nuclear doctrine was to make potential enemies understand the inevitability of retaliation for an attack on Russia or its allies.

The Kremlin spokesperson Dmitry Peskov appeared to directly suggest that Russia might respond with nuclear weapons if Ukraine used western-supplied missiles to strike targets inside Russia.

“The use of western non-nuclear missiles by Kyiv against Russia, under the new doctrine, could provoke a nuclear response,” he said.

Peskov also stressed that any attack on Russia by a non-nuclear state with the participation of a nuclear state would be considered a joint attack. “Russia has always viewed nuclear weapons as a deterrent, the use of which is an extreme, forced measure,” Peskov said.

Lavrov said he hoped Moscow’s new nuclear doctrine would be “attentively read” in the west.

As both Moscow and Kyiv mark the 1,000th day of Russia’s full-scale invasion, Peskov also said that Russia would defeat Ukraine.

Putin frequently invoked Moscow’s nuclear arsenal, the world’s biggest, in the early days of its invasion of Ukraine, pledging repeatedly to use all means necessary to defend Russia. He later appeared to moderate his rhetoric, but officials close to the Russian president recently told Nato countries they risked provoking nuclear war if they were to give the green light for Ukraine to use long-range weapons.

Britain is also expected to supply its own Storm Shadow missiles for use by Ukraine on targets inside Russia, after the US approval.

While Moscow has vowed retaliation, analysts suggest its options are limited, with the country unlikely to resort to the nuclear option.

“The most predictable and obvious will be an increase in strikes on Ukrainian cities and civilian infrastructure facilities in anticipation of the winter cold,” said political analyst Anton Barbashin.

He added that the use of western-supplied long-range weapons is unlikely to serve as a definitive red line for Moscow.

“Strikes with long-range Atacms missiles on the territory of Russia ... are more likely to fall into the list of red lines that will be crossed and will cease to be red lines,” Barbashin said.

Western officials also believe Russia may escalate its ongoing campaign of arson and sabotage targeting Europe.

Intelligence agencies are currently investigating recent damage to two undersea fibre-optic communication cables in the Baltic Sea, severed in rapid succession earlier this week. Some officials have already suggested Kremlin involvement.