N. Korea bolsters combat drills: source

North Korea has recently stepped up its combined military exercises in regions close to South Korea and increased surveillance over their border, Yonhap News reported citing its source Wednesday.

Its leader Kim Jong-il inspected a special forces drill at an eastern coastal city in mid-April while naval and air forces have bolstered their joint training based on a war scenario off the west coast, the source said, demanding anonymity.

"North Korea is intensifying its military training despite its economic difficulties," the South Korean military source said, adding Kim visited the city of Wonsan on April 15 to observe an Army drill.

Kim, 67, who reportedly suffered a stroke last year, visited the city about 90 kilometers north of the inter-Korean border to inspect "industrial facilities," North Korean state media had said on April 27.

"Overnight special forces marches on mountains were stepped up in the area," the source said, adding North Korean naval and air forces have also increased "practical training" in the west.

"The Navy appears to be stepping up exercises off the island of Chodo with a hypothetical target in mind," he said. Chodo is the largest North Korean island along the country`s southwestern coast.

"The Navy and the Air Force are training jointly based on a war plan," he said, noting the country routinely checks its war plans through joint exercises between the Army, the Air Force and the Navy.

"It appears that North Korea`s combat readiness is at its peak," the source added.