South Korea on Tuesday urged communist North Korea to stop disturbing its military and mobile communications, calling alleged jamming attempts "unacceptable."

Seoul's defence ministry this month accused the North of beaming signals across the tense border to trouble military communications during an annual US-South Korea joint military exercise.

"The North's jamming of GPS signals causes inconveniences among our people, poses threat to their safety... and is an unacceptable act in breach of international customs," Korea Communications Commission said in a statement.

It will send a letter of protest Tuesday to Pyongyang in which it will urge the North to "stop the attempts immediately and prevent recurrence," the Commission said.

South Korean mobile users complained of bad connections and the military reported GPS (Global Positioning System) navigational devices malfunctioning on March 4.

The North calls the military exercise a rehearsal for invasion.

South Korea's then Defence Minister Kim Tae-Young said last year the North's jamming devices, modified from Russian technology, were capable of disrupting guided weapons and they posed "a fresh security threat" to the South.

Cross-border tension has been acute since the North's alleged sinking of a Seoul warship that killed 46 sailors in March 2010 and the shelling of a border island that left four South Koreans dead in November.

earlier related report
N. Korea ready to discuss uranium programme
Seoul (AFP) March 15, 2011 - North Korea has told a visiting Russian envoy that it was willing to discuss its uranium enrichment programme at six-party disarmament talks, state media said Tuesday.

"(North Korea) is willing to come to the six-party talks unconditionally," Pyongyang's foreign ministry said in a statement published by the official Korean Central News Agency.

At talks with Russian Deputy Foreign Minister Alexei Borodavkin, the North said it did not "object to the issue of the uranium enrichment programme" from being discussed at the six-party forum, a ministry spokesman was quoted as saying.

The Russian envoy visited the North between Friday and Monday, meeting with Foreign Minister Pak Ui-Chun and other North Korean officials, according to the South's Yonhap news agency.

Pyongyang sparked security fears in November when it disclosed an apparently functional uranium enrichment plant to visiting US experts.

The North said it was a peaceful energy project but experts said it could hand Pyongyang a second route to making atomic bombs on top of its existing plutonium stockpile.