South Korea's Ministry of Unification confirmed that the North was no longer answering calls to the hotline, reports Yonhap news agency.

BBC: North Korea cuts military hotline with South

"We have said several times that the U.S.-South Korean military exercises are annual defensive exercises, " Kim Ho-nyun, spokesman for South Korea's Ministry of Unification, said at a news briefing Monday.

CNN: N. Korea warns against intercepting 'satellite' launch

"To threaten military action against a civilian aircraft that is flying under international air regulations is not only against international laws but is an inhumane action, " said Kim Ho-Nyun, a Ministry of Unification spokesman.

CNN: S. Korea reroutes flights, cites 'threat'

Song Young Dae, a onetime assistant minister at South Korea's Ministry of Unification and a former negotiator, admits that it is difficult to judge from Seoul how serious an opposition Kim faces or whether he faces any opposition at all but points to a number of signs that the North Korean leader is in control.

CNN: Kim Jong Il's New Direction

The Unification Ministry said a schedule for the return of staff from the Kaesong plant hadn't been completed, and that the South remains open to dialogue with the North to restart the plant.

WSJ: Seoul to Pull Workers out of North Korea

Seoul, South Korea (CNN) -- South Korea's Unification Ministry on Friday rejected a demand from the North to repatriate nine of its citizens who defected to the South by boat over the weekend.

CNN: South Korea won't return 9 defectors from the North

More than 840 South Koreans were set to cross the border Monday to Kaesong, which provides a badly-needed flow of hard currency to a country where many face food shortages, according to Seoul's Unification Ministry.

NPR: SKorea, US Begin Drills As NKorea Threatens War