North Korea is facing one of the worst economic crises in its 73-year history, amid shortages of food and medicines and warnings of rising unemployment and homelessness.

The country’s economy has been battered by more than a year of border restrictions imposed after the coronavirus outbreak, flooding caused by natural disasters, and international sanctions imposed in response to the regime’s nuclear and ballistic missile programmes.

Last month, the North Korean leader, Kim Jong-un, called on ruling party members to wage another “arduous march” to stave off an economic crisis, which he likened to a 1990s famine in which up to three million people are thought to have died.

While groups monitoring the North say they have seen no evidence of an unfolding humanitarian disaster, observers with contacts inside the country believe worsening conditions are coinciding with a crackdown by a regime fearful of a repeat of the social upheaval that followed the famine.

“There are many obstacles and difficulties ahead of us, and so our struggle for carrying out the decisions of the eighth party congress would not be all plain sailing,” Kim told grassroots members of the ruling Korean Workers’ party, according to the state-run KCNA news agency.

Kim, who is facing the biggest domestic test of his nine years in power, said he had instructed party members at every level “to wage another, more difficult arduous march in order to relieve our people of the difficulty, even if just a little”.

The term “arduous march” is a euphemism used to describe the aftermath of the 1990s famine, which was caused by the fall of the Soviet Union – then a leading aid provider – economic mismanagement and disasters. The estimated death toll ranges from the hundreds of thousands to between two and three million people.

The North sealed its land borders with China and Russia early last year after the first reports of Covid-19 cases in the Chinese city of Wuhan. While the closures and restrictions on people’s movements inside the country appear to have prevented the pandemic from taking hold, they have devastated its import-dependent economy.

“The North Korean economy is on the brink of a huge recession,” said Jiro Ishimaru, who heads the Osaka-based Asia Press website and operates a network of citizen journalists in North Korea.

Ishimaru said the near-collapse of trade with China had caused significant job losses, with people forced to sell possessions and even residency rights to their state-owned homes to buy food.

Data shows North Korea’s trade with China shrank by about 80% last year after Pyongyang sealed its borders, knowing that significant virus cases would quickly cripple its already weak health infrastructure.

“A lot of people are suffering,” Ishimaru said. “I have spoken to contacts who say there are more people begging for food and money at markets, and a rise in the number of homeless people. There is also a desperate need for antibiotics and other medicines.”

Kim, who has been unusually candid about the “worst ever” challenges facing North Korea, appears to be using anti-Covid measures – with strict limits on people’s movements – to strengthen his grip on power, amid concern inside the regime that a prolonged economic crisis could cause a breakdown in social order.

“Kim Jong-un promised the North Korean people in 2012 that they would never have to tighten their belts again,” said Leonid Petrov, a North Korea expert and senior lecturer at the International College of Management, Sydney.

“Obviously, nobody could envisage that a global pandemic would compound international sanctions, so the assumption that the ‘arduous march’ is coming back is designed to mobilise party members to work harder to prevent disaster.”

Gaining an accurate picture of conditions in the country has been made more difficult by the departure of large number of diplomatic staff and aid workers during the pandemic.

North Korea continues to report that it has not identified a single case of Covid-19, but US and South Korean officials have cast doubt on those claims.

Russia’s ambassador to Pyongyang, Alexander Matsegora – one of the few diplomats still in the country – said in April that life in North Korea was “difficult”, but that there were no signs of a repeat of the 1990s famine.

“Thank God, it is a long way from the ‘arduous march’, and I hope it will never come to that,” he told Russia’s Tass news agency. “The most important thing is that there is no famine in the country today.”

Kim’s reference to the famine was an ideological call to arms rather than a serious prediction of impending disaster, said Leif-Eric Easley, an associate professor of international studies at Ewha University in Seoul.

“He was not crying ‘famine’, but rather demanding national unity for increasing domestic production,” Easley said. “Kim is also using North Korea’s self-imposed Covid isolation to clean house of foreign influences he considers subversive to his rule.”

There are signs that North Korea is trying to rebuild its economic lifeline with China – its main ally and aid donor – including the resumption of a cross-border cargo train service and the construction of quarantine facilities that would allow supplies to be brought in by truck.

China is keen to avoid economic collapse in the North in case it triggers a humanitarian crisis and political turmoil that could end in the peninsula being controlled by South Korea and the US. “China and Russia cannot afford to lose North Korea to the US and its allies in the region,” Petrov said.