South Korea's defense ministry said Friday that North Korea is continuing to jam Global Positioning System signals in a bid to raise tensions.

The announcement comes after Seoul issued a warning late Thursday as it detected signs that North Korea has been engaged in radio jamming operations against the South. It said the North's actions have been ongoing for about a month "North Korea is expected to continue to disrupt GPS signals in South Korea for a while in a bid to raise tension on the peninsula," Moon Sang-gyun, a ministry spokesman, said in a regular press briefing.

The disruptions could cause mobile phones to malfunction and affect planes and ships that rely on GPS for navigation. The areas affected are near the inter-Korean border regions close to the North.

South Korea's ICT ministry on Friday said the disruption affected 58 airplanes and 52 vessels in South Korea, although there has been no reported significant mishaps so far.

"There has been no reported problems in the military or limitation to our military capability," Moon said. "But if the North's GPS jamming results in real damage to airplanes or ships, we will make the North pay a due price."

Pyongyang is believed to possess more than 10 kinds of GPS-jamming devices, according to a military official. Seoul said that the communist country first conducted GPS jamming operations in 2012.

The North's provocation came as the U.N. Security Council imposed the toughest sanctions against the North last month over its January nuclear test and long-range rocket launch in February.

The North has been also ratcheting up its threats against South Korea and the United States over their ongoing joint military drills. The North has long denounced them as a rehearsal for a northward invasion, a charge denied by Seoul and Washington.

South Korea's military said that North Korea has been sending the disruptive signals from Haeju, a port city of the country's southwest area and Mount Kumgang on the east coast.

"South Korea's military has sensors in place to detect North Korea's GPS jamming operations and is responding to the North's move by sharing information with relevant government agencies," the defense ministry said.

The Ministry of Unification called on the North to immediately suspend its "provocation."

"North Korea's move to jam GPS signals itself is a provocation," Jeong Joon-hee, a ministry spokesman, told a regular press briefing. "The North should immediately end such provocative acts."

There is speculation that a unit under North Korea's Reconnaissance General Bureau might be behind the North's latest move. The North's reconnaissance bureau is tasked with espionage operations against South Korea and cyberwarfare.

Jeong declined to comment on the speculation, saying that it is related to military intelligence. (Yonhap)