South Korea and US joint military drills have begun, amid rare family reunions between North and South Korean relatives separated for decades.
The annual military exercises will last until April 18.
They will involve Key Resolve, a computer-based simulation, and Foal Eagle, which involves air, ground and naval drills.
Pyongyang is opposed to the drills and had previously threatened to cancel the reunions if the exercises went ahead.
The military drills will involve more than 12,500 US troops.
The US and South Korea describe the annual drills as defensive in nature, but Pyongyang has described them as “exercises of war”.
Last year, the exercises led to a prolonged surge in tensions, with North Korea threatening pre-emptive nuclear strikes and attacks on South Korean and US targets.
The rhetoric this year has so far been relatively mild, but the drills are scheduled to last until April, and many here see them as the toughest test yet of whether ties between the two Koreas are warming.
South Korea and US annual military exercises will last until April 18
Speaking on Monday, South Korean Defense Ministry spokesman Kim Min-seok said: “As of now, there are no unusual movements from North Korea. We will only take action against North Korea if it makes provocations or denunciations.”
Also on Monday, around 360 South Koreans met their North Korean relatives for the first time since the 1950-1953 Korean War, at a family reunion event in North Korea’s Mount Kumgang resort.
They were the second set of relatives chosen to attend the reunions, which come amid an apparent thaw in inter-Korean ties.
Many people were separated from their relatives by the division of the Korean peninsula after the Korean War.
Pyongyang has been accused of using the family reunions, which are highly emotional events, as a bargaining chip.
North Korea has in the past canceled the reunions after the South took actions it opposed – most recently in September.
Meanwhile, South Korea also offered to assist the North with tackling an outbreak of foot-and-mouth disease.
North Korean state media said that thousands of pigs had been affected by the disease.
South Korea, which has also been hit by outbreaks before, has offered to send aid, including medical goods and vaccines, officials said.
North Korea has decided to indefinitely postpone scheduled reunions of families separated by the Korean War, a government statement has said.
The statement did not provide details other than accusing unidentified conservatives in South Korea of “hostility” towards Pyongyang.
North Korea regularly makes such claims about the South.
The postponement is an apparent setback after weeks of gradually improving ties between the two countries.
The South Korean government has not yet responded to the announcement.
Relations reached a low point earlier this year when the North cut a military hotline to the South in March. That followed its third nuclear test in February, which triggered international sanctions.
The two Koreas were due to hold six days of family reunions from 25-30 September for people separated by the 1950-53 Korean War, following which millions of people were separated from their families by the dividing of the peninsula.
North Korea has decided to indefinitely postpone scheduled reunions of families separated by the Korean War
But the North’s Committee for the Peaceful Reunification of Korea was quoted as saying: “We postpone the impending reunions of separated families until a normal atmosphere is created for talks and negotiations to be able to move forward.”
“As long as the South’s conservatives deal [with] inter-Korean relations [with] hostility and abuse… such a basic humanitarian issue as family reunions cannot be resolved.”
Correspondents say the reunions would have been a highly symbolic event and would have been the first in three years for families separated by the war.
The reunion programme was suspended after the North’s shelling of a South Korean border island in November 2010.
It is estimated that there are about 72,000 South Koreans – nearly half of them aged over 80 – on the waiting list for a chance to join the family reunion events.
But only a few hundred participants are selected each time. Most do not know whether their relatives are still alive, because the two countries prevent their citizens from exchanging mail, phone calls and emails.
The reunions are often tearful and emotional occasions, correspondents say, in which North and South Koreans usually meet in the North for two or three days before the South Koreans head home again.
The reunion programme began in 2000 and sporadic events since then have seen about 17,000 relatives briefly reunited.
North Korea and South Korea have begun talks on resuming the reunions of families separated by the Korean War in 1950-53.
Korean Red Cross officials met at the border village of Panmunjom in an attempt to restart the reunions last held in October 2010.
The two sides remain technically at war because the conflict ended in an armistice and not a peace deal.
The talks come as the two countries last week reached a deal on a joint industrial zone.
Many families were separated at the end of the war by the dividing of the peninsula.
South Korean President Park Geun-hye last week called for the resumption of the reunions, urging North Korea to “open its heart”.
The aim is for some of them to meet during a festival holiday in September.
North Korea and South Korea have begun talks on resuming the reunions of families separated by the Korean War in 1950-53
However, the two sides have yet to agree on the venue, size and date of the possible reunions.
In South Korea, than 70,000 people have registered for the reunions.
Kim Kyung-ryun said that she had been trying for decades to reunite with her parents and siblings in the North.
“So many reunions have passed, and I’ve never been picked,” she said.
“So I wonder whether my chance will ever come, and I’m just a bit too tired to worry about it now.”
The current talks are the latest signs of tensions easing on the peninsula.
In April, North Korea withdrew its workers from the Kaesong joint industrial zone, angered by the expansion of UN sanctions after its February 12 nuclear test and annual US-South Korea military drills.
The deal reached last week came after six rounds of talks ended unsuccessfully.
Meanwhile, it was reported that a North Korean man apparently defected after he was found on South Korea’s Gyodong Island.
It was not immediately known how he had crossed the border in stormy weather. South Korean officials said he was now being questioned.
Defections by crossing the border via land and sea is said to be rare, and most are made by North Koreans entering another country before going to South Korea.
North Korea has agreed to South Korea’s proposal to resume reunions of families separated since the 1950-1953 war, official media in Pyongyang say.
The reunion meetings would take place in the Chuseok holiday on September 19.
South Korea’s President Park Geun-hye called last week for the resumption of the reunions, last held in 2010.
Her appeal followed an agreement to reopen a joint industrial plant, the latest step in the easing of tension between the two countries.
The latest statement on the reunions came from North Korea’s Committee for the Peaceful Reunification of Korea.
North Korea has agreed to South Korea’s proposal to resume reunions of families separated since the 1950-1953 war
It said: “The reunion of separated families and their relatives shall be made in Mt Kumgang resort on the occasion of the upcoming Harvest Moon Day.”
Talks will take place on August 23 at Mt Kumgang to prepare for the reunions.
The statement also called for the resumption of tourist trips to Mt Kumgang.
It said: “The Kaesong Industrial Zone and the tours to Mt Kumgang resort are valuable works common to the nation which should not be delayed as they are symbols of reconciliation, unity, reunification and prosperity.”
The Kaesong Industrial Complex is home to 123 South Korean factories which employ more than 50,000 North Korean workers. The inter-Korean joint project is a key source of revenue for Pyongyang.
North Korea withdrew its workers in April, angered by the expansion of UN sanctions after its 12 February nuclear test and annual US-South Korea military drills.