SINGAPORE >> South Korea warned Saturday that any future attacks by North Korea would be met by a very strong response, saying that Pyongyang is becoming increasingly bold in its provocations.

South Korea must react to any future attacks by the North with stiffer responses than in the past, Defense Minister Kim Kwan Jin said at a regional security conference in Singapore.

“Proactive deterrence means that if there is a provocation, we will respond very strongly,” Kim said. “I don’t think we can be reserved because they are being bolder and bolder.”

Tensions between the two countries that share the Korean peninsula have jumped since two deadly attacks blamed on North Korea last year. The North has denied involvement in the sinking of a warship in March 2010 that killed 46 South Korean sailors and argued that a November artillery barrage that killed four was provoked by South Korean firing drills.

In remarks earlier Saturday at the IISS Shangri-La Dialogue security forum, U.S. Defense Secretary Robert Gates said North Korea’s development of long-range missiles and nuclear weapons put the country “in the process of becoming a direct threat to the United States.”

Gates said the U.S. is seeking to persuade North Korea to follow international norms through negotiations with the participants in stalled six-nation nuclear disarmament talks that involve the two Koreas, Japan, China, Russia and the U.S.

“The United States has no interest in regime change,” Gates said. “We have no interest in destabilizing North Korea.”

North Korea vowed Friday to launch “retaliatory military actions” against South Korea, a threat that came days after Seoul said its military had used photos of Pyongyang’s ruling family for target practice.

“From now on,” the North “will launch practical and overall retaliatory military actions to wipe out the group of traitors at a stroke,” said a statement from an unidentified spokesman for the general staff of the North’s Korean People’s Army.

South Korean marines and some army units had used pictures of North Korean leader Kim Jong Il, his son and heir-apparent Kim Jong Un, and his father, the North’s revered founder Kim Il Sung, as firing targets since the North’s deadly shelling of a South Korean border island in November. The South said Tuesday that it would tell units to use only standard targets.

Kim Kwan Jin said North Korea has been insincere in previous talks and must change its attitude for South Korea to return to formal discussions.