NEW YORK, SEOUL • North Korea warned at the United Nations on Monday that the deployment of three United States aircraft carriers in joint navy drills with South Korea was fuelling tensions that could lead to nuclear war.

Mr Ja Song Nam, North Korea's ambassador to the UN, said in a letter to UN Secretary-General Antonio Guterres that this was "the worst-ever situation prevailing in and around the Korean peninsula".

The first such deployment of three US carriers since 2007 "is making it impossible to predict when nuclear war breaks out due to the US nuclear war equipment" taking up a "strike posture", wrote the ambassador.

The four-day exercise in the western Pacific involving the USS Ronald Reagan, USS Nimitz and USS Theodore Roosevelt began last Saturday and included seven South Korean vessels, including three destroyers.

Mr Ja said the US had reactivated round-the-clock sorties by B-52 strategic bombers and was making frequent flights of B-1B and B-2 bombers in South Korea's airspace.

"The large-scale nuclear war exercises and blackmails... make one conclude that the option we have taken was the right one and we should go along the way to the last," wrote Mr Ja.

He accused the council of "turning a blind eye to the nuclear war exercises of the US, who is hell-bent on bringing a catastrophic disaster to humanity".

Meanwhile, Mr Joseph Yun, the US' special representative for North Korea policy, arrived in Seoul yesterday and was slated to meet South Korean and international officials, according to the US State Department, although there is no indication that the top US negotiator's visit will include talks with the North.

Seoul's Foreign Ministry said Mr Yun is scheduled for talks with his South Korean counterpart Lee Do Hoon on Friday on the sidelines of an international conference on disarmament, jointly hosted by the ministry and the UN on the resort island of Jeju.

South Korea-born Mr Yun has been at the heart of reported direct diplomacy in recent months with Mr Kim Jong Un's regime in North Korea. Using the so-called "New York channel", he has been in contact with diplomats at Pyongyang's UN mission.

Mr Yun's visit comes as a North Korean soldier was shot and critically wounded while defecting to the South on Monday.

The soldier has since undergone several surgical procedures and is in a critical condition, South Korea's government and military said yesterday, adding that he is expected to survive.

"Until this morning, we heard he had no consciousness and was unable to breathe on his own, but his life can be saved," said Mr Suh Wook, chief director of operations at South Korea's Joint Chiefs of Staff. Five bullets had been extracted from the soldier's body so far, leaving an estimated two inside, Mr Suh added.

The unarmed soldier had sped towards the border in a vehicle when a wheel came loose, forcing him to escape on foot while under fire from four North Korean soldiers who shot around 40 rounds at him, Mr Suh said. South Korean officials have yet to identify exactly where the soldier came from and what his intentions were.

Mr Suh also said the South had later informed the North on Monday about the soldier and his ongoing treatment via loudspeakers installed at the border. No South Korean or US soldiers were wounded during the incident, and North Korea's military did not show any unusual movements yesterday.

AGENCE FRANCE-PRESSE, REUTERS