South Korea has vowed to retaliate “strongly” against any provocation from North Korea after Pyongyang declared a “state of war”, drawing an even thinner line in the restive peninsula.

South Korean president Park Geun-hye said she had instructed the military on Monday to immediately respond to the North’s provocations, reports the Financial Times.

“If there is any provocation… there should be a strong response in initial combat without any political considerations,” Park told defense officials in Seoul.

“As the country’s military commander, I will trust the judgement of our military who is directly facing the North’s sudden and unpredictable provocations,” she added.

The United States – South Korea’s ally which it conducted joint military exercises with – also deployed a destroyer capable of shooting down missiles off the southwestern coast of the Korean peninsula in response to heightened tensions in the Korean peninsula, AFP reports.

US F-22 Raptor stealth fighters and B-2 bombers were also deployed to South Korea as part of the ongoing military drill.

North Korea had threatened to strike the US mainland and US bases in the Pacific in its latest ramping up of rhetoric against the “US imperialists”.