Chaos on North Korean border as shots fired at fleeing soldiers by South Korea

's military has fired warning shots after soldiers crossed the rivals' border, South Korean officials have said. In a statement, South Korea's said about 10 North Korean soldiers headed back north after South Korea blasted out warning broadcasts and fired warning shots.

The statement said the North Korean soldiers violated the military demarcation line at the eastern section of the border at 5pm local time (8am GMT). South Korea's military said it is closely monitoring North Korean activities.

A motive for Tuesday's border crossing by North Korean soldiers wasn't immediately clear. The 155-mile (248km) long, 2.5 mile (4km) wide demilitarised zone between the two countries is the world's most heavily armed border.

An estimated two million mines are peppered inside and near the border, which is also guarded by barbed wire fences, tank traps and combat troops on both sides. It is a legacy of the Korean War, which ended with an armistice and not a peace treaty.

Bloodshed and violent confrontations have sometimes happened at the heavily fortified border. When Pyongyang's troops briefly violated the border in June last year and prompted South Korea to fire warning shots, it didn't escalate into a major source of tensions.

South Korean officials decided the soldiers didn't deliberately commit the border intrusion, the point at which they entered was a wooded area and military demarcation line signs there weren't clearly visible. South Korea said the North Koreans were carrying construction tools.

Tensions between the Koreas are running high as North Korean leader Kim Jong Un continues to flaunt his military nuclear capabilities and align with Russia over President Vladimir Putin's war on Ukraine.

Kim is also ignoring calls by Seoul and Washington to resume denuclearisation negotiations.

US President Donald Trump has said he will contact Kim again to revive diplomacy. North Korea has not responded to Mr Trump's remarks and claims US hostilities against the country have deepened since the US President was inaugurated in January.

Meanwhile, South Korea is experiencing a leadership vacuum after the ousting of President Yoon Suk Yeol after his ill-fated . South Korea will hold a snap presidential election on June 3 to choose his successor.

The announcement from acting President Han Duck-soo came four days after the Constitutional Court unanimously removed Yoon from office, which by law must be followed by an election within 60 days. The next president should serve a full five-year term.

Deep political polarisation will likely shape the election into a two-way race between Yoon's People Power Party and its chief liberal rival, the Democratic Party, which holds a majority in the country's National Assembly.

It looks set to be an uphill battle for the People Power Party as it struggles to restore public confidence and heal internal wounds left by Yoon's short-lived enactment of martial law.