The possibility of large numbers of seaborne refugees from North Korea, among them possible spies, was also discussed by Japanese ministers.
Against this backdrop, South Korean stocks closed the week down 0.64 percent, while the local currency dropped 10.3 Korean won against the USA dollar. Markets in Hong Kong, Singapore and other Southeast Asian countries were closed.
And when North Korea shelled the South Korean border island of Yeonpyeong in 2010, some South Koreans stocked up on dried food and canned goods, fearing the skirmish could escalate into a full-blown war.
In addition, the country will commemorate the 105th anniversary of the birth of its founder, Kim Il-sung, on Saturday and the 85th anniversary of the founding of the Korean People's Army on April 25.
South Korea has also stepped up its military preparations and is calling for closer cooperation and intelligence sharing betwen the United States and Seoul.
Embattled O'Reilly takes his longest spring break in years
None said they had spoken to a manager or to human resources personnel about their position. James organized a protest outside Fox News headquarters in NY on Wednesday evening.
Satellite imagery showed activity at North Korea's Punggye-ri testing site, a sign the secretive regime could be preparing for another nuclear test, analysts from the USA research institute 38 North wrote.
On Friday, neighboring China's foreign minister, Wang Yi, warned that tensions between the USA and North Korea had escalated to such a point that "a military conflict may start at any moment".
On Thursday, US intelligence officials told NBC that two American destroyers armed with Tomahawk cruise missiles are positioned some 480 kilometers from North Korea's nuclear test site.
"If the USA comes with reckless military maneuvers then we will confront it with the DPRK's preemptive strike", Ryol said. On Thursday, benchmark US crude rose 7 cents to close at $53.18 per barrel in NY.
CURRENCIES: The dollar bounced back after weakening against major currencies following President Donald Trump's comment in an interview with The Wall Street Journal that the dollar was "getting too strong".
The euro edged up 0.1 percent to $1.0617.