In his first personal response to recent threats from North Korea, South Korean President Lee Myung-bak has criticized Pyongyang's recent attitude.  Amid reports of potential military measures by the North, Mr. Lee is calling for a new, more "straightforward" relationship between the two sides. VOA's Kurt Achin reports from the South Korean capital.

The South Korean media quotes a senior North Korean military official, Thursday, as warning that Pyongyang may take what it calls "military countermeasures" in an escalating exchange of rhetoric between the two sides.

President Lee Myung-bak during meeting at presidential office in Seoul, 03 Apr 2008

Much of the North's anger is focused on recent testimony by South Korean Joint Chiefs of Staff Chairman Kim Tae-young, who told lawmakers there are contingency plans to strike North Korea's nuclear weapons sites, if it became clear the North seems poised to attack.  North Korea has demanded an apology for those remarks.

In his first public comments on the latest tensions, President Lee defended Kim's testimony.

He says what Kim said can be seen as a natural and ordinary reply, and the North should not interpret it differently.  Therefore, says Mr. Lee, the North's attitude is "undesirable."

Mr. Lee's policy toward North Korea is considerably firmer than his two predecessors, who transferred billions of dollars in aid and investment to Pyongyang with few strings attached.  He told a luncheon of top military officers, Thursday, he wants to transform the North-South relationship.

Mr. Lee acknowledges that North-South tensions have risen since his February inauguration, but says he does not expect them to get any worse.  He says his administration wants a "more straightforward" dialogue with North Korea, and that the North should "open its mind."

North Korea invaded South Korea in 1950.  The resulting war was never formally concluded, only halted by a 1953 armistice.  The United States deploys about 28-thousand troops in South Korea to deter any repeat invasion by the North.

It is unclear precisely what North Korea may have meant Thursday, with its reported threat of "military countermeasures."  However, U.S. General Burwell Bell -- Commander of American forces in Korea - warns the North should not make the mistake of using force against the South.

"Should North Korea attack, we will defeat the attack quickly and decisively, and end the fight on terms set by the alliance," General Bell said.

Experts believe the North's military is unlikely to attack, but may be contemplating a restriction in North-South contact by closing off border access points which it controls.