North Korea has been boosting defenses on its east coast, South Korea’s Yonhap news agency said on Tuesday, after the North said U.S. President Donald Trump had declared war and that it would shoot down U.S. bombers flying near the Korean peninsula.

Tensions have escalated on the Korean peninsula since North Korea conducted its sixth and most powerful nuclear test on Sept. 3, but the rhetoric has reached a new level in recent days with leaders on both sides exchanging threats and insults.

North Korean Foreign Minister Ri Yong Ho said Trump’s Twitter comments, in which the U.S. leader said Ri and leader Kim Jong Un “won’t be around much longer” if they acted on their threats, amounted to a declaration of war and that Pyongyang had the right to take countermeasures.

Yonhap suggested the reclusive North was in fact bolstering its defenses by moving aircraft to its east coast and taking other measures after U.S. bombers flew close to the Korean peninsula at the weekend.

The unverified Yonhap report said the United States appeared to have disclosed the flight route of the bombers intentionally because North Korea seemed to be unaware. South Korea’s National Intelligence Service was unable to confirm the report immediately.

Ri said on Monday the North’s right to countermeasures included shooting down U.S. bombers “even when they are not inside the airspace border of our country”.

“The whole world should clearly remember it was the U.S. who first declared war on our country,” he told reporters in New York on Monday, where he had been attending the annual United Nations General Assembly.

“The question of who won’t be around much longer will be answered then,” he said.

[Source: Reuters]