North Korea has quarantined 380 foreigners in an attempt to stop the coronavirus from breaking out.
The foreigners are mostly diplomats stationed in the capital Pyongyang, state media reported.
About 200 foreigners had already been confined to their compounds for the past 30 days - but as that came to an end, the quarantine has been extended.
North Korea has not reported any cases of Covid-19, but several other countries did so on Monday.
Afghanistan and Dubai said they had detected their first cases, and Kuwait said three people returning from Iran had been infected.
In South Korea, seven people have died with 763 people infected. Around 7,700 troops have been quarantined after 11 military members were infected.
The virus, which emerged in China, has spread to at least 29 countries. Italy has the highest number of coronavirus cases in Europe, with 152.
Around 50,000 people in two northern "hotspot" regions - Veneto and Lombardy - have been put under quarantine for two weeks.
Iran has also confirmed 43 cases of the virus and eight deaths.
In the Chinese city of Wuhan, where the virus emerged, the authorities earlier announced that some non-residents would be allowed to leave if they showed no symptoms of the virus.
However, local officials now say that order was made without authorisation and has been revoked.
The city has been in lockdown since January 23, with authorities cutting off transport links in and out of the city.
More than 2,500 people have died from the virus in mainland China, with some 77,150 cases confirmed cases reported.
What is the situation in North Korea?
North Korea has not confirmed any cases but the country shares a long and often porous border with China. There are concerns that North Korea, which is subject to international sanctions, lacks the health infrastructure to test and treat those infected and that any outbreak could quickly spread unchecked.
At the moment, all foreigners coming into the country must be quarantined for 30 days.
There are relatively few foreigners in North Korea, and only around 200 Westerners, according to one expert.
North Korean authorities have also cancelled the annual Pyongyang marathon, which typically sees people from all over the world participating.
Around 3,000 people in North Pyongan province - a north-western region bordering China - are also now under monitoring for reportedly showing suspected symptoms, said state media.
What about South Korea?
South Korea has the largest number of confirmed cases outside China, after a huge spike in the past week.
Before last Wednesday, the country had recorded just 31 cases. That number has now jumped to 763.
Eight new cases of the virus have been reported in the army, and one in the navy, air force and marine corps - bringing the number to 11.
But the biggest virus clusters have been linked to a hospital and a religious group near the south-eastern city of Daegu.
A handful of South Korea airlines, including Korean Air Lines - the country's biggest airline - has suspended flights going to Daegu, which has a population of around 2.5m.
Korean Air says the suspension will last until March 27.
What's happening in Italy?
Italian officials have introduced sweeping measures to control what is now the worst outbreak of the coronavirus in Europe - at least three people have died and more than 150 cases confirmed.
In the regions of Lombardy and Veneto, a lock-down is in place in several small towns. For the next two weeks, 50,000 residents will not be able to leave without special permission.
Even outside the zone, many businesses and schools have suspended activities, and sporting events have been cancelled - including several top-flight football matches.
Officials have yet to find the first carrier of the virus in the country.
World edges closer to coronavirus pandemic
Analysis by Fergus Walsh, medical correspondent
The combined situation in South Korea, Iran and Italy points to the early stages of pandemic. This means a global outbreak, with the coronavirus spreading in the community in multiple parts of the world.
In each of these countries we are seeing spread of the virus with no connection to China. The lockdown efforts in Italy mirror those that have happened in China.
The situation in Iran is especially worrying, because the health authorities have reportedly said the virus has spread to multiple cities, and it appears the first case in Lebanon is linked to a traveller from Iran.
If we have a pandemic, it will still be important to limit the speed of spread of the virus.
If countries could hold it somewhat at bay until the end of winter, there is a hope that warmer temperatures will reduce the time the virus can survive in the air, as we see with seasonal flu. But this may not be certain.
What's the latest from Iran?
Iran said on Sunday it had 43 confirmed cases of the virus, most of them in the holy city of Qom. Eight of those infected have died, the highest number of deaths outside China.
Iraq, Pakistan, Armenia and Turkey have closed their borders with Iran, and Afghanistan has suspended air and road travel to and from Iran.
What about China, where the outbreak started?
China's President Xi Jinping has described the outbreak as the "largest public health emergency" in the country's recent history.
Speaking on Sunday, he acknowledged "shortcomings" in China's response and said lessons must be learned.
China reported 409 new infections on Monday, the bulk of which were from Wuhan.
But outside China, cases with no clear link to that country or other confirmed cases continue to rise, prompting concern from the World Health Organization (WHO).
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