South Korea is opting for a low public policyprofile amid escalating tensions with North Korea. Seoul officials kept quiet, a day after Pyongyang threatened to turn the South into "ashes."

South Korean officials kept relatively silent Monday, just 24 hours after North Korea's official media warned of a "powerful preemptive attack" against the South.

The North Korean commentary warned Sunday if it attacks, "everything will turn into ashes, not just a sea of flames." The language echoes North Korean threats in past years to turn South Korea into a "sea of fire."

The threats are a response to testimony last week by South Korean Joint Chiefs of Staff Chairman Kim Tae-young.

Kim tells a panel of legislators the South has contingency plans to preemptively strike suspected North Korean nuclear weapons sites, if it becomes apparent the North intends to make use of those weapons against the South. South Korean military leaders have since tried to downplay those remarks.

The flare-up over preemptive strikes is part of a broader political landscape of heightening tensions between North and South Korea, which never formally ended their 1950-53 war.

South Korean officials refused to confirm Monday a report in South's largest daily newspaper that North Korean jet fighters have flown close to the heavily armed North-South border at least ten times since conservative President Lee Myung-bak was inaugurated last month.

Mr. Lee has taken a much stiffer policy line with North Korea than his two predecessors, who transferred billions of dollars in aid and investment to Pyongyang with little or nothing requested in return.

This month, Mr. Lee's top official on North Korea policy warned a joint North-South industrial zone would not be expanded unless there is progress in diplomacy to get rid Pyongyang's nuclear weapons capabilities. In response, North Korea expelled most of the South Korean officials in charge of managing the zone, located in the North Korean city of Kaesong.

South Korean media did quoted senior military officials as saying the South may soon issue some type of general expression of regret for the recent worsening of North-South relations. However, they say it will not be an apology, and that the South will not deviate from its "practical" principles on dealing with the North.

Dong Seung-young, a North Korea expert at the private Samsung Economic Research Institute, says the world may just have to get used to chilly North-South relations for a while.

He says even if the stalled relations last a long time, President Lee's government places top priority on "fixing" South Korean policy toward the North.

Mr. Lee's political allies say ten years of lenient treatment toward Pyongyang made it easier for the North to test a nuclear weapon in 2006. Now, with North Korea four months late in providing a promised nuclear declaration, they say a firmer approach is needed.

President Lee may get a firmer mandate in his North Korea policies from legislative elections next month, in which which his conservative party is expected to make gains. Some experts say the North's recent moves may be aimed at influencing that vote.

Others, like Professor Yang Moo-jin of Seoul's University of North Korean Studies, say Pyongyang is trying to influence South Korea's relationship with the United States.

He says North Korea is trying to send a signal that strengthening the U.S. - South Korea alliance is not the best way to solve the nuclear issue. He says Pyongyang wants to convince U.S. and South Korean leaders not to seek ways of pressuring the North when they meet at an upcoming summit.

President Lee is scheduled to meet with President Bush in Washington next month. The chief U.S. delegate to the nuclear talks, U.S. Assistant Secretary of State Christopher Hill, is scheduled to arrive Tuesday in Seoul to meet with officials here.