US mobilises troops as tension between two Koreas escalates

The United States on Friday started mobilising its troops in South Korea after North Korean leader Kim Jong-un ordered his troops to be on a war footing as tensions with South Korea escalated following an exchange of fire across the border.

North Korea on Thursday afternoon first fired a single round believed to be from an anti-aircraft gun, which landed near a South Korean border town, Seoul said.

About 20 minutes later, three North Korean artillery shells fell on the southern side of the demilitarised zone dividing the two Koreas. South Korea responded with dozens of 155-milimeter artillery rounds, according to South Korean defence officials.

The immediate trigger for the North Korean action was the installation of certain propaganda loud speakers on the South Korean side of the border.

North Korea has given South Korea until 5:00pm on Saturday to dismantle the propaganda speakers. South Korean authorities installed the loudspeakers at an unidentified site on the western front line bordering North Korea, have vowed to continue with the broadcasts. They have been blaring out propaganda since 1 August.

Tension has been rising after an exchange of artillery shells across the border.

The two Koreas have been technically at war for the past 65 years, as the 1950-53 Korean conflict ended with a ceasefire that was never ratified by a formal peace treaty.

Kim had given similarly bellicose orders in the past, most recently in 2013 when he declared "a state of war" with the South, although it did not lead to any clashes.

Any war between North and South Korea, however, 'could go nuclear,' experts warn.

Meanwhile, the International Crisis Group said earlier today there was a significant number of US troops mobilising in the region. US troop vehicles were seen in the South Korean town of Paju bordering North Korea, reports said.

Korean Central News Agency said the government has ordered mobilisation of troops who are "ready to attack" South Korea.

"The Korean People's Army (KPA) front-line large combined units entered into a wartime state all at once, fully armed to launch surprise operations, and wound up their preparedness for action," it said in a statement.

Korean Central News Agency says the government has ordered mobilisation of troops who are "ready to attack" South Korea.

On the ground, however, there did not seem to be any sort of tension between the two countries.

But the South Korean won fell nearly 1.8 per cent against the dollar since yesterday, according to reports.