Did You Know
Did You Know
South Korea has begun shutting down its operations in the Kaesong industrial park jointly run by the rival Koreas.
On Wednesday, Seoul announced it would suspend its activity there because of the North's recent rocket launch.
It had already restricted some South Korean activity there following Pyongyang's nuclear test last month.
It is unclear how long the shutdown will last, which Seoul said was aimed at cutting off money the North used for nuclear and missile development.
About 124 mostly South Korean companies operate in Kaesong employing thousands of North Koreans.
The BBC's Steve Evans in Seoul says South Korean companies have started taking out easily-moveable equipment and stocks of finished goods and raw materials.
Many North Korean workers failed to turn up for work today. Their South Korean managers cleared their desks and started to leave, our correspondent adds.
Some of the managers from the South told the BBC they were shocked by the suddenness with which their businesses in the North had had to cease production.
The shutdown came as the US Senate voted unanimously in favour of tougher sanctions against North Korea.
The draft legislation targets any person or entity trading or financing anything related to weapons of mass destruction, conventional arms proliferation, North Korea's rocket programme, money laundering, narcotics trafficking, human rights abuses, activities that threaten US cyber security, and the import of luxury goods.
All were already sanctioned, but the measures aim to tighten the restrictions.
The bill also authorises $50m (£34m) for radio broadcasts into North Korea and humanitarian aid programs.
The House of Representatives passed a similar bill last month. The two will now have to be reconciled into a final measure needing President Barack Obama's sign-off.
Republican Senator Cory Gardner, one of the authors of the latest sanctions bill, criticised President Obama's policy of "strategic patience''.
"The situation in the Korea peninsula is at its most unstable point since the armistice,'' he said, referring to the deal to end hostilities in the Korean War in 1953.
Republican senators and presidential candidates Ted Cruz and Marco Rubio interrupted campaigning to go back to Washington DC for the vote. But Democratic candidate Bernie Sanders did not return, although he did express his support for the bill in a statement.
Congress has been keen for sanctions to be tightened since North Korea tested a nuclear device in January. Last weekend, the North launched a long-range rocket, which it said was designed to put a satellite into orbit, but critics say it was to test ballistic missile technology.
But with vastly more North Korean trade being done with China than with the US, politicians admitted that measures were intended in large part at demonstrating resolve to Beijing - Pyongyang's biggest ally and trading partner, and a permanent UN Security Council member reluctant to significantly step up sanctions.
Japan also toughened its sanctions on the North this week, including by restricting remittances from members of its Korean community to North Korea, and a ban on North Korean ships entering Japanese ports.