US Flies Surveillance Aircraft over Korean Peninsula to Monitor North Korea

The US Air Force's RC-135W Rivet Joint was spotted in skies above the South's capital area at around 10 a.m., No callsign tweeted, Yonhap news agency reported.

On Saturday, North Korean leader Kim Jong-un held a closed meeting of the party's Central Military Commission "to discuss the key issues of further bolstering a war deterrent of the country," the North's Korean Central News Agency reported the following day.

The deployment of such reconnaissance aircraft by the United States is part of its regular operations, but it might have let some of them be spotted to put pressure on the North, according to sources and experts.

Military sources here said North Korea has not shown unusual military movements in recent weeks, after leader Kim Jong-un put military action plans against the South on hold last month.

In June, tensions on the peninsula escalated sharply, as Pyongyang blew up an inter-Korean liaison office and threatened to take military action in anger over anti-regime propaganda leaflets sent via balloons from the South.