Officials rage at the West for allowing Ukraine to attack deep within Russia as fears simmer on the streets.

Last week, a defence industry site in the central Ukrainian city of Dnipro was struck by a Russian medium-range ballistic missile, which President Vladimir Putin described as a response to “NATO’s aggressive actions against Russia”.

Early reports that Dnipro was hit by an intercontinental ballistic missile proved inaccurate.

Moscow’s deployment of the new weapon, named Oreshnik, followed a series of Ukrainian rocket strikes into western Russian territory using United States-supplied ATACMS long-range missiles, targeting military facilities in the regions of Bryansk and Kursk.

In his statement, Putin acknowledged that the Ukrainian attacks caused casualties among Russian troops.

“I’m scared,” said a young St Petersburg resident who requested anonymity.

Like many Russians, she has family in Ukraine.

“It’s especially infuriating because … my whole family is in Ukraine,” she told Al Jazeera. “When [Russian missiles] are flying there, it really sucks, and when [Ukrainian missiles are] flying here, it’s scary. There’s no happy medium in this situation.

“There was hope that everything would gradually begin to calm down because nothing has flown to my [Ukrainian] hometown, Zaporizhzhia, for a long time. And now it’s started again with twice the intensity. In my head is purely chaos, of course.”

But others appeared less concerned about the escalation, which some observers fear could transform into a Russian nuclear standoff with NATO.

“I don’t think rockets will fall either on Moscow or on London although [Ukrainian] drones are already flying over Moscow,” said Dasha, a Muscovite in her early 30s who asked Al Jazeera to withhold her surname.

“But you know when they say there will be a third world war, Russia will come for Switzerland, all of that, I don’t think so, but let’s wait and see. What’s happening now is of course totally f*****.”

Evgeniya, in her 60s, said her life is going on as normal.

“I don’t pay attention to such things. Nobody knows what will happen, so why panic? I just went on a long holiday from Moscow to [St Petersburg].”

Even so, there are some who echo the Kremlin’s warnings.

“I think that [this mess] will catch up with the West,” said 51-year-old Alec, a St Petersburg resident.

Russian lawmaker warns of ‘most dangerous stage’, blames US

In mid-November after months of hesitation, outgoing US President Joe Biden finally gave Kyiv the green light to fire ATACMS on targets in Russia. At the same time, the United Kingdom granted Kyiv permission to use long-range Storm Shadow missiles within Russian territory.

Angered by the moves, Putin signed off on Russia’s new nuclear doctrine days after the UK and US allowed Kyiv to use the cruise missiles to attack Russia.

Under the amendments, Russia has lowered the threshold for using its nuclear arsenal.

Russia and its ally Belarus can now consider a nuclear response if they are conventionally attacked by a nonnuclear state, such as Ukraine, that is aided by a nuclear power. Several of the NATO countries supporting Ukraine, the US and UK included, possess nuclear weapons.

Although the new protocols had been in the works since September, the implementation during the missile exchange between Russia and Ukraine raised the stakes in the war, which has raged on for nearly three years.

“I believe right now we are in the most dangerous stage for the simple reason they have a lame duck in the United States,” lawmaker Konstantin Kosachev told CNN on Thursday. “Biden and his people want to become part of a, let’s say, positive and resultative history in their interpretation.”

On his talk show, the pro-Kremlin TV host Vladimir Solovyov mocked the West by joking about sinking the British Isles with Russia’s Poseidon nuclear torpedo.

“I want to see Poseidon,” he gestured vividly.

“It would be so beautiful. The beauty of that wave, the glow of radiation.”

It is a threat that top Russian officials, including Dmitry Medvedev, the former president and current deputy chairman of Russia’s security council, have made several times before.

‘Unlikely to result in a major escalation’

But Oleg Ignatov, a Russia expert at the International Crisis Group, said a few more intensified Ukrainian attacks into Russia are unlikely to change the course of the war.

“The consensus before Ukraine was granted authorisation was that authorisation would not change anything militarily,” he told Al Jazeera from Moscow.

He explained that Kyiv is likely to secure little more than “political and moral dividends” from the attacks because the range and number of missiles Ukraine has are limited.

“Sporadic point attacks using a small number of missiles are unlikely to result in a major escalation,” he said. “I think a crisis could arise if Ukraine strikes with a large number of missiles at once, causing major damage, or if a single strike causes major casualties among the Russian military or civilian population. Then Russia could go further down the escalation ladder.”

Meanwhile, Washington and the Kremlin have an interest in containing the conflict, he said.

“I think both Putin and the West want to avoid nuclear escalation and direct conflict between Russia and NATO,” he continued.

“In this respect, nothing has changed for either Russia or the West. Biden is thinking how to help Ukraine but at the same time to avoid a confrontation scenario with Russia. Putin is thinking about how to maintain the advantage in Ukraine but at the same time to prevent NATO’s involvement in the conflict.”

The deployment of Oreshnik was a “signal” suggesting to the US that Russia is prepared to go further if Biden pushes the boundaries of “what is acceptable”, he said, but ultimately “both sides are unwilling to go further.”

In the now-exiled Russian newspaper Novaya Gazeta, atomic weapons expert Pavel Podvig argued that Putin could veer towards the nuclear option to achieve strategic, but not tactical, goals – in other words, terrifying the enemy into submission rather than merely altering the course of a battle – if the scope of the conflict widens to include NATO countries.

But if he resorts to such a strategy, he would risk alienating countries otherwise sympathetic to and willing to work with Russia, Podvig wrote.