The United States has flown a surveillance aircraft over South Korea, an aviation tracker said Tuesday, on an apparent mission to monitor North Korea.

The US Navy P-3C maritime surveillance plane was spotted in the skies over the peninsula on Monday, Aircraft Spots tweeted.

It is the latest in a series of US operations seemingly aimed at monitoring the North after the communist nation warned of a "new strategic weapon" and "shocking actual action" against the US.

Denuclearization negotiations between Washington and Pyongyang remain stalled after the second summit between North Korean leader Kim Jong-un and US President Donald Trump collapsed without a deal last year.

In a New Year's Day announcement, Kim has said he no longer sees a reason to stick to his earlier commitment to suspend nuclear and intercontinental ballistic missile tests. (Yonhap)