WASHINGTON (Yonhap News) ― Responding to the new North Korean leadership’s threats to eschew dialogue with South Korea, the United States called Friday for Pyongyang to improve inter-Korean relations.

“We continue to monitor the situation on the peninsula and are in close contact with our ally, the Republic of Korea. We share a common interest in ensuring regional peace and stability. We continue to urge North Korea to take steps to improve its relations with its neighbors,”a State Department official told Yonhap News Agency on the customary condition of anonymity.

The U.S. response came hours after the North’s powerful National Defense Commission announced that the communist regime would never deal with South Korea’s Lee Myung-bak administration.

The Lee government did not send a formal mourning delegation to the North after the death of its ”Dear Leader,“ Kim Jong-il, on Dec. 17.

Seoul also blocked South Koreans from visiting the North to pay respects to Kim, except for former first lady Lee Hee-ho and Hyun Jeong-eun, the chairwoman of Hyundai Group, long engaged in business in the nation.

The commission also said there will be no change in Pyongyang’s policy under the stated leader Kim Jong-un, the third and youngest son of Kim Jong-il.

It was the first statement issued by the commission, which is the most powerful organization under the North’s Constitution, since the launch of the new leadership. It is also very unusual for the commission to release a statement for the outside world.

The White House did not reply to Yonhap’s repeated requests for comments on the North’s position.

In a report, meanwhile, a U.S. Congress-affiliated think tank said Kim’s death has put the Barack Obama administration at a crossroads again in its policy toward the nuclear-armed, recalcitrant nation.

”The United States faces a range of options, many of which are necessarily mutually exclusive, but all of which entail risks,“ the Congressional Research Service (CRS) said.

It added Kim’s death can be viewed as ”something of a Rorschach test for one’s opinion of North Korea policy.“

Among various policy choices is the so-called ”subversive engagement,“ which is less antagonistic than increasing outright pressure on Pyongyang, the CRS said.

It would involve Washington and Seoul aggressively attempting to further delegitimize the North’s regime by increasing elite and ordinary North Koreans’ exposure to the outside world through such policies as increasing joint economic ventures, radio broadcasts, swamping North Korean markets with South Korean digital media, and setting up exchange and visitor programs, said the CRS.

”An advantage of these options is that many of them could be combined with any other approach, be it hard engagement or hard pressure,“ it said. ”A disadvantage is that they likely will take years to have an impact, and in the meantime many could channel funds and support to the regime.“

More ambitiously, if the U.S. succeeds in negotiations with the North, according to the CRS, it could empower more moderate forces inside the nation by allowing them to present diplomatic and economic achievements as an alternative to more bellicose options.

”Most, though by no means all, North Korea watchers doubt the likelihood of this optimistic scenario,“ it said.