Loudspeakers blaring hygiene messages, foreign ambassadors locked in their compounds and state media demanding “absolute obedience” to health authorities – North Korea is taking what diplomats call “unprecedented” measures as it seeks to prevent a crippling coronavirus outbreak.

The authoritarian state, led by the ruling Kim family since its foundation in 1948, maintains extensive control over the lives of its citizens and is pulling out all the stops to try to protect itself from the virus that first emerged in neighbouring China, long its key diplomatic ally and trade partner.

After the virus emerged it quickly closed its borders, cutting itself off from the outside world in a move diplomats and analysts say is its best method of self-protection given the weakness of its health infrastructure.

Arrivals are subject to 30 days’ isolation and it has stepped up its efforts internally, with the official Korean Central News Agency describing an intensifying “anti-virus campaign”, including door-to-door health check-ups and loudspeaker vans instructing citizens on hygiene practices around the country.

Foreigners are facing tough restrictions – all of those resident in the country have been subjected to quarantine at their premises since the beginning of February.

Diplomats in Pyongyang have unable even to walk around the city in what the Russian Ambassador to North Korea Alexander Matsegora described as a “morally crushing” situation.

The embassy had been “left without diplomatic mail . . . we did not manage to get medicines and supplies for our first-aid post”, he told Russia’s TASS news agency.

Staff could only leave the premises – which have a prime location in Pyongyang’s Taedonggang district close to the Workers’ Party leadership compound – to take rubbish to a landfill, when “Korean specialists immediately disinfect our truck at the gates of the embassy”.

The city’s Orthodox church, taekwondo gym, skating rink and swimming pool were all off-limits, as were Korean and painting classes. “They may seem trifles, but everyday life is made of them.”

Diplomatic work had been virtually suspended, he added, with no meetings, conversations or negotiations with North Korean officials or other embassies, while contact with the authorities was limited to phone calls or official notes dropped into a special mailbox.

Only a country as “unique” as the North could take such a decision to address “a problem of national importance” and implement it, he said, describing the situation as “extraordinary”.

“In material terms, self-isolation is of course very expensive for the Korean state,” he added.

But it would always be willing to pay that price, he went on: “It is very important to understand that the issues of state security, the ideology and dignity of the country – in its North Korean understanding, of course – always and definitely prevail over economic considerations.”

Those who expect sanctions to force the North to make concessions over its nuclear arsenal – negotiations between Pyongyang and Washington are currently deadlocked – should recognise that reality, he added.

South Korea has seen a rapid surge of Covid-19 cases in recent days, to more than 1,250, giving it the largest national tally outside of China.

But Pyongyang insists that it remains the only one of China’s neighbours not to have had a single case.

Observers doubt that, but the Rodong Sinmun, the official mouthpiece of the Workers’ Party, urged citizens to show “absolute obedience” to instructions from health authorities and the state.

“We should bear in mind that any moment of complacency could result in irreversible catastrophic consequences and should maintain a high state of alert,” it said.

Earlier this week it warned of “devastating consequences” if the country suffers even one case of coronavirus, recommending that people avoid gathering in public places – even restaurants.

“Sitting down and dining together and talking with each other can itself become the main spreading ground of the infectious disease,” it said.

But state duties do not appear to be subject to such restrictions – on Wednesday it carried pictures of scores of Supreme People’s Assembly officials lining up to visit the supposed birthplace of Kim Jong-il, the father and predecessor of the current leader Kim Jong-un, at Mount Paektu.