North Korea on Friday called for the withdrawal of US troops from South Korea, saying their prolonged presence could spawn an "all-out war".

The US troops' presence has turned the Korean peninsula into "the world's biggest hotspot", the North's foreign ministry said in a statement carried by the official Korean Central News Agency.

"If the US seeks to keep its forces in South Korea, contrary to the unanimous desire of the regional people, it had better get itself ready to taste an all-out war with (North Korea)," it said.

Some 28,500 US troops are based in the South under a mutual defence pact, which was signed during the 1950-53 Korean War. The Koreas have been technically at war since the conflict ended in an armistice, without a subsequent peace treaty being signed.

The ministry described the US troop presence as "the most vivid expression of the US hostile policy" toward the nuclear-armed North.

The US policy will only force the North to bolster its "nuclear deterrent, making the prospect for solving the nuclear issue on the Korean peninsula gloomier", it said.

The North has been developing nuclear weapons for decades. Its official position has been that it needs them for self-defence against a US nuclear threat.

Pyongyang disclosed in November 2010 an apparently operational uranium enrichment plant, in addition to its plutonium stockpile.

S. Korea offers to send flood aid to N. Korea
Seoul (AFP) Sept 7, 2012 - South Korea has proposed sending emergency relief aid to North Korea, the first such offer since ties sank into a deep freeze after the death of the North's leader last December.

The South's Red Cross chief sent a proposal on Monday calling for talks with North Korea on the shipment of aid, the Unification Ministry, which handles cross-border affairs, said Friday.

Official aid from the South to the North often goes through the Red Cross as a matter of formality.

South Korea last sent such aid two years ago, although civilian groups have been allowed to ship aid to the impoverished North despite high cross-border tensions.

Minister Yu Woo-Ik told parliament Pyongyang had not yet reacted to the offer.

"We have conveyed our willingness to help North Korea's efforts to overcome flood damage," he said, adding a drought this spring and floods this summer appeared to have brought severe damage to the North.

Yu's comment came a day after his ministry approved a request from Christian relief group World Vision to send 500 tonnes of flour to North Korean flood victims next week.

Pyongyang's state news agency said earlier that floods in June and July left 569 people dead or missing and washed away or inundated 65,280 hectares (161,310 acres) of cropland.

A strong typhoon which hit the Korean peninsula last Tuesday killed 48 people and damaged at least 50,000 hectares of farmland in the North, it said on Monday.

North Korea suffers chronic food shortages, with the situation exacerbated by floods, droughts and mismanagement. During a famine in the mid to late-1990s hundreds of thousands died.

Last year the North rejected the South's proposal to provide flood aid saying the offer did not include cement or food staples like rice. Seoul fears rice and cement can be diverted to the military.

Relations remain frosty, and there has been no substantial cross-border dialogue since the North's new leader Kim Jong-Un came to power.