LONDON/SEOUL - North Korea has asked embassies in Pyongyang that might wish to get staff out if there is a war to submit plans to it by April 10, Britain said on Friday, as it upped the pressure as part of a war of words that has set the Korean peninsula on edge.Initial reports by Russia's Foreign Ministry and China's Xinhua news agency suggested that North Korea had suggested that embassies should consider closing because of the risk of conflict.The request came amid a military buildup by the United States in South Korea following the North's warnings that war was inevitable due to UN sanctions imposed for a nuclear test and what it terms "hostile" US troop drills with South Korea."We believe they have taken this step as part of their continuing rhetoric that the US poses a threat to them," Britain's Foreign Office said in a statement after the reports from Russia and China.A British diplomatic official, who spoke on condition of anonymity, said that European Union embassies in Pyongyang had been summoned to deliver their evacuation plans.Under the Vienna Convention that governs diplomatic missions, host governments are required to facilitate the exit of embassy staff in the event of conflict.Russia's Foreign Ministry said earlier that North Korea had "proposed that the Russian side consider the evacuation of employees in the increasingly tense situation", according to Denis Samsonov, a spokesman for its embassy in Pyongyang. A report from Chinese state news agency Xinhua chimed with the Russian report, saying that Pyongyang had asked embassies to consider evacuation if the situation deteriorated.North Korea, ruled by 30-year old Kim Jong-un, has not issued any statement indicating which of the conflicting reports was true.Two rockets deployedIn a fusillade of statements issued over the past month, North Korea has threatened to stage a nuclear strike on the United States, something it lacks the capacity to do, according to most experts, and has declared war on South Korea.On Friday, South Korean media reported that North Korea had placed two of its intermediate range missiles on mobile launchers and hidden them on the east coast of the country in a move that could threaten Japan or U.S. Pacific bases.The report could not be confirmed. But any such movement may be intended to demonstrate that the North, angry about joint U.S.-South Korean military exercises as well as the sanctions for its third nuclear test, is prepared to demonstrate its ability to mount an attack.Speculation centered on two kinds of missiles neither of which is known to have been tested. One was the so-called Musudan missile which South Korea's Defence Ministry estimates has a range of up to 3,000 km (1,865 miles, the other is called the KN-08, which is believed to be an inter-continental ballistic missile, which is again untested.The month-long verbal assaults from North Korea have set financial markets in South Korea, Asia's fourth largest economy, on edge.South Korean shares slid on Friday, with foreign investors selling their biggest daily amount in nearly 20 months, hurt after aggressive easing from the Bank of Japan sent the yen reeling, as well as by the tension over North Korea."In the past, (markets) recovered quickly from the impact from any North Korea-related event, but recent threats from North Korea are stronger and the impact may therefore not disappear quickly," Vice Finance Minister Choo Kyung-ho told a meeting.While few observers believe that North Korea will launch a military attack, alarm has grown over the intensification of the threats.The comments from the North could well continue until the end of April when the joint US and South Korean military exercises are due to end."The rhetoric is off the charts," said Victor Cha, former director for Asian affairs at the White House National Security Council and now senior adviser at the Centre for Strategic Studies in Washington.The youth of Kim Jong-un has become an issue. He is the third member of his family to rule in Pyongyang and took over in December 2011 after the death of his father Kim Jong-il, who staged confrontations with South Korea and the United States throughout his 17-year rule.Counterbalancing that, the young Kim is surrounded by generals and advisers in their 70s who have been through this before, but there are concerns that he may view the risk of conflict as one worth taking."We don't understand this new guy at all. And if the North Koreans move to provoke the South, the South is going to retaliate in a way we haven't seen before," said Victor Cha, a former director for Asian affairs at the White House National Security Council.