North Korea has said it cannot assure the safety of embassies in Pyongyang after 10 April, and has urged Britain, Russia and other European nations to evacuate diplomatic staff amid soaring nuclear tensions.
Countries across Europe on Friday reported receiving a letter suggesting they pull out of Pyongyang, as an increasingly bellicose North Korea moved two mid-range missiles to its east coast.
"Their communication said that from April 10, the North Korean government would be unable to guarantee the safety of embassies and international organisations in the country in the event of conflict," a spokeswoman for Britain's Foreign Office said.
"Our understanding is that the North Koreans were asking whether embassies are intending to leave, rather than advising them to leave."
Britain was considering its next steps, she said, while reminding North Korea of its responsibilities under the Vienna Convention to protect diplomatic missions.
Russia, which has relatively close ties with North Korea, also received the missive.
Foreign Minister Sergei Lavrov said Moscow was in close contact with its partners including China over the suggestion..
"The suggestion was made to all embassies in Pyongyang and we are trying to clarify the situation," Russian news agencies quoted Lavrov as saying on a visit to Uzbekistan.
"We are in close contact with our Chinese partners as well as the Americans", and all participants in the frozen six-party talks process seeking peace on the peninsula, he added.
He said there were "many factors" that needed clarification.
The spokesman of the Russian embassy in Pyongyang, Denis Samsonov, told Russian news agencies that a representative of the North Korean foreign ministry "suggested that the Russian side examine the question of evacuating the employees of the Russian embassy."
He said the mission had taken note of the information and was working normally. "We are currently in the process of taking the decision," said Samsonov, adding that the current situation in Pyongyang was "absolutely peaceful".
A Russian foreign ministry source was quoted as saying by the Interfax and RIA Novosti news agencies that the security of Russian citizens was the priority in the taking of any decision.
"Unfortunately, the situation (on the Korean peninsula) is not developing in the way that we would like. For us the security of our citizens is the priority," said the unnamed source.
In Sofia, a foreign ministry spokesman said North Korea has sent letters to Bulgaria and other EU countries telling them to consider pulling their diplomatic staff from Pyongyang for security reasons.
"Yes, we -- along with other EU member states -- have received such a letter signed by a deputy foreign minister of the Democratic People's Republic of Korea," Foreign Ministry Spokesman Dimitar Yaprakov told AFP.
He said all foreign ambassadors had been summoned by Pyongyang's foreign ministry "telling them that it was ready to assist them if they wanted to evacuate their missions."
"The chiefs of EU missions to Pyongyang are meeting tomorrow there to discuss a common position and common action," he added.
The Czech foreign ministry also confirmed receiving the statement.
"I can confirm the information," spokesman Karel Srol told AFP in Prague.
"Each Czech embassy has a detailed plan of what to do in a crisis. If the situation required such steps, they would be taken," Srol said, confirming that the Czech embassy in Pyongyang has four employees.
Russia on Thursday made its harshest criticism yet of North Korea in the current crisis, describing Pyongyang's actions as "categorically unacceptable".
Moscow retains relatively close ties with North Korea which go back to the Soviet Union when Soviet forces occupied the northern part of the Korean peninsula at the end of World War II, leading to the creation of a pro-Moscow communist North Korean state.
But Russia also shares a short border with North Korea south of Vladivostok in its Far Eastern region and has clearly been irritated by the country's recent bellicose behaviour.