N Korea worker killed in Kaesong

Some 30,000 workers are employed in the Kaesong complex

A North Korean worker was killed and four others were injured in an accident in the Kaesong industrial complex in North Korea, Southern officials said.

It happened when a steel frame collapsed at a factory owned by a South Korean company, Pyeongan, on Wednesday.

An investigation into the cause of the accident is reportedly under way.

Some 30,000 North Koreans workers are employed by South Korean companies in the complex, which lies just across the border between North and South.

Two of the four injured are in critical condition, a spokesman for South Korea's Unification Ministry said, according to Associated Press.

They are all being treated in a hospital in the zone.

The accident may raise questions about safety standards in the zone, which as a joint venture between North and South Korea - still technically at war - has as much political as economic significance.

It comes in a low ebb of North-South relations, which have soured in the months since South Korean President Lee Myung-bak took office.

Last week a South Korean woman was shot dead by North Korean soldiers while holidaying in the North Korean resort of Kumgang.