Seoul and Washington were to begin annual joint military exercises on Monday, defying warnings from Pyongyang that the war games would jeopardise nuclear negotiations between the US and North Korea.

The drills come after Pyongyang tested a series of short-range projectiles in recent days, calling one of them a “solemn warning” to Seoul against pursuing the mainly computer-simulated drills with Washington.

After a year of mutual threats and mounting tensions US President Donald Trump and the North’s leader Kim Jong Un held a historic meeting in Singapore last year, when Kim signed a vague pledge to work towards “denuclearisation of the Korean peninsula”.A second summit in Hanoi in February broke up amid disagreement on sanctions relief and what the North might be willing to give up in return.

Under the US-South Korea security treaty an American general will take command of their combined forces in the event of war, but Seoul has long sought to reverse the position.

Trump and Kim agreed to resume nuclear talks during their impromptu June meeting in the Demilitarised Zone that divides the peninsula, but that working-level dialogue has yet to begin.

The nuclear-armed North–which attacked its neighbour in 1950, triggering the Korean War has always been infuriated by military exercises between the US and the South, decrying them as rehearsals for invasion.