The US and South Korea have begun a major military exercise in the Sea of Japan, despite threats of retaliation from North Korea.
The navy and air force manoeuvres involve 20 ships, 200 planes and 8,000 US and South Korean personnel.
Washington and Seoul say they want to send a clear signal to the North following the sinking of a South Korean warship in March.
An international investigation said a North Korean torpedo sank the ship.
However, the claim has been angrily denied by Pyongyang.
reported by A PAKISTAN TIMES
On Saturday, North Korea threatened to use its nuclear deterrent in a retaliatory, "sacred war" in response to the exercise.
The BBC's John Sudworth, who is aboard one of the warships, says the show of strength is intended to rattle Pyongyang's military and political elite.
But some observers are questioning whether the display of military power will simply galvanise the hardliners inside the isolated country, he says.
North Korea's inflammatory rhetoric is nothing new, he adds, but the rising tension is causing concern, with China urging all parties to show restraint.
The South Korean defence ministry said the manoeuvres had been relocated from the sensitive Yellow Sea to the Sea of Japan following protests from China, North Korea's ally.
