SEOUL, South Korea (CNN) -- North Korea cut off dialogue with South Korea on Thursday, claiming the peninsula was on the brink of another war.

North Korea is taking aim at South Korea, claiming the peninsula is on the brink of another war.

North Korea also accused South Korea of driving their relationship to "confrontation and catastrophe." The country said it was stopping dialogue after South Korea failed to apologize for remarks one of its generals made this week.

The general said South Korea would attack suspected nuclear weapons sites in North Korea if the North tried to attack the South with atomic bombs.

The communist nation said it would take unspecified "military actions" to punish South Korea.

The news comes as South Korean President Lee Myung-bak called for dialogue in the midst of escalating tensions between the two nations.

"What we want is a straightforward talk with North Korea," Lee said, according to South Korea's Yonhap news agency. "We want the North to come to the dialogue table with a more sincere attitude."

North Korea has bristled in response to Lee's promised tougher stance toward the North. He took office in late February.

For its part, North Korea has accused Seoul of taking on pro-U.S. policies.

"South Korea's conservative regime is driving the north-south relations to confrontation and catastrophe, blatantly swimming against the trend of the era of independence, reunification, peace and prosperity," an unidentified spokesman for the Democratic Front for the Reunification of the Fatherland said in a statement broadcast by state-run media in North Korea. The group sometimes serves as a mouthpiece for the government.

Two days earlier, the communist nation called Lee "a traitor."

On March 27, North Korea expelled 11 South Korean officials from a joint industrial park in Kaesong, North Korea. That move came after South Korea's unification minister said it would be hard to expand the park without North Korean progress on de-nuclearization. The next day, North Korea fired a barrage of short-range missiles of its western coast.

Then state-run television in North Korea warned that it would turn parts of South Korean into "ashes" in the event of a pre-emptive South Korean strike on its nuclear sites. Watch the war of words escalate among the two Koreas »

That threat came in apparent response to comments from a senior South Korean military official that South Korea would attack suspected nuclear weapons sites in North Korea if the north tried to attack the South with atomic bombs.

Lee called North Korea's threats "undesirable" on Thursday during a meeting of the country's ranking generals, Yonhap reported.

"Since my inauguration, North Korea has intensified tension across the border," Lee said. "But I don't expect the situation to deteriorate further."

The two countries have technically remained in a state of war since the Korean War ended in 1953, although relations have warmed somewhat in the last eight years. The Korean conflict ended in a truce, but no formal peace treaty was ever signed.

Leaders of the two nations held an historic summit in 2000, paving the way for the reunification of some families who were separated during the war. A second summit followed in October 2007, but concerns over North Korea's nuclear program have loomed over interactions between the two countries.

North Korea agreed last year to dismantle its nuclear program in exchange for economic aid and better relations with the United States. North Korea still must finish the nuclear disablement process for the first phase of the agreement.

Last week, U.S. State Department spokesman Sean McCormack said North Korea has made an "incredible amount of progress" on disablement, but still must complete the process. E-mail to a friend

All About South Korea • North Korea • Nuclear Proliferation • Lee Myung-bak