The South Korean military says it has located the stern of its warship¹ that sank in mysterious circumstances on Friday following an explosion.

韩国军方称，他们已经确定上周五意外爆炸的军舰船尾的沉没位置。

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South Korea has not given up all hope of finding survivors

The authorities are hoping that some of the 46 crew members still missing may be alive but trapped in underwater air pockets in the wreckage³（残骸） .

Military diving teams were due to begin a search for survivors.

The vessel⁴（船舶，飞机） sank close to the sea border with North Korea; the South says it is open-minded on the cause of the blast.

Rescue officials said on the weekend that the explosion had broken the ship into two parts, which had sunk to the seabed.

Rescue race

The BBC's Korea correspondent, John Sudworth, said navy divers⁵ had been hampered⁶（限制，阻碍） by strong currents and murky⁷（黑暗的，朦胧的） waters, but had now located the stern, lying on the sea bed.

It is the part of ship that contains the sleeping compartments⁸, so thought to be the most likely location in which survivors might be found.

But it is now a race against time, our correspondent says.

If any of the 46 missing crew members are still alive, calculations suggest that any oxygen in the trapped air will soon run out.

The 1,200-tonne Cheonan naval⁹ patrol vessel sank near the disputed（有争议的） maritime¹⁰ border with North Korea but military officials say there is no indication the North was involved.

Our correspondent says that although the two navies have exchanged fire along the sea border in recent years, no unusual military movements were detected on Friday night, leading to speculation¹¹（推测，思索） that the sinking was due to some kind of accident.

Whatever the cause, as well as a disaster for the South Korean navy, it is moment of terrible, personal tragedy for the families of the missing, their trauma¹²（外伤，创伤） , and sometimes anger, played out on national television as the whole country waits for answers.

Tensions rise

At his latest emergency briefing on the rescue, the South Korean president has urged all available personnel and equipment to be mobilized to search the sunken ship（沉船） as soon as possible.

Meanwhile, North Korea has accused the South of psychological warfare¹³（心理战） for allowing journalists to enter the two countries' demilitarised zone, and warned of "unpredictable incidents".

"If the US and the South Korean authorities persist in their wrong acts to misuse¹⁴ the DMZ（非军事区） for the inter-Korean confrontation¹⁵ despite our warnings, these will entail¹⁶ unpredictable incidents including the loss of human lives in this area for which the US side will be wholly to blame," the statement said.

Dramatic warnings from the North are not unusual - on Friday the North had threatened "unprecedented¹⁷ nuclear strikes".

However, they are dissected¹⁸（解剖，仔细检查） by Korea-watchers for hints of movement on the primary issue of importance to North Korea's neighbours - it's readiness to re-enter talks about how to end its nuclear programmes.

Separately, North Korea's Foreign Ministry¹⁹ issued a statement on Monday castigating²⁰（严惩，苛评） the United Nations for its criticism of the North's human rights record.

South Korea recognises the Northern Limit Line, drawn²¹ unilaterally（单方面地） by the US-led United Nations Command to demarcate the sea border at the end of the Korean War. The line has never been accepted by North Korea.