Seoul, South Korea ? North Korea agreed today to work with South Korea to peacefully resolve the international standoff over Pyongyang’s nuclear programs, as U.S. envoys stepped up diplomatic efforts elsewhere.

But after the two Koreas issued a joint statement pledging cooperation, the South Korean government acknowledged that the agreement fell short of commitments it sought from the North during the Cabinet-level talks.

In the declaration, the two sides said they had “sufficiently exchanged” positions on the nuclear issue and “agreed to actively cooperate to resolve this issue peacefully.”

Meanwhile, a top American diplomat visited Tokyo to strengthen international support for putting the issue before the U.N. Security Council. The push comes as top officials in Washington say they detect a softening in North Korea’s stance.

This week’s Cabinet-level meetings in Seoul were the first in months between the two Koreas, and South Korea promised to make them a forum for insisting North Korea scrap nuclear programs that could make weapons.

The two sides agreed to hold the next round of talks April 7-10 in Pyongyang and another round of inter-Korean economic talks Feb. 11-14 in Seoul. Both sides also pledged to work toward reconciliation on the Korean peninsula, which has been divided since 1945.

In a separate statement, the South Korean negotiators said they had been unable to win any compromises from the North. The South had been pressing the North to state specific steps for settling the international standoff peacefully.

“Although we have not been able to draw out a more progressive position on North Korea’s nuclear issue, we have sufficiently delivered our and the international community’s concern on the nuclear issue,” the negotiators said.

The South Korean side also said it would work with Japan and the United States to resolve the issue peacefully and encourage North Korea to abide by its international obligations.

North Korean chief delegate Kim Ryong Song, left, toasts with South Korean Unification Minister Jeong Se-hyun, center, and an unidentified South Korean official during a dinner for the Cabinet-level talks at the Walkerhill Hotel in Seoul. The top negotiators said Thursday they had made progress toward clearing the threat of insecurity on the peninsula.

The ongoing Cabinet-level meetings have been seen as a chance for South Korea to broker a solution. But North Korea has repeatedly said it will only deal directly with the United States.

Rhee Bong-jo, spokesman for the South Korean delegation, said this week’s discussions could only go so far because the North largely stuck to that position.

At a dinner break late Thursday, South Korean delegation head Jeong Se-hyun urged the North to make a clear statement on the nuclear impasse.

“We must completely remove the security concerns which have been formed on the Korean Peninsula recently,” Jeong said.

North Korean delegation leader Kim Ryong Song agreed it was vital to “prevent the danger of war on the Korean Peninsula and preserve the safety of the nation.”

Separately, negotiators from both countries met Thursday in the North Korean capital to discuss completing railroad and road links. The projects began as part of a reconciliation process stemming from a North-South summit in June 2000.

Tensions escalated in October when the United States said North Korea admitted having a secret nuclear program in violation of a 1994 agreement. The United States and its allies suspended oil shipments to the North, and Pyongyang responded by expelling U.N. inspectors and preparing to restart a 5-megawatt nuclear reactor to generate badly needed electricity.

North Korea is believed to already have produced two nuclear weapons and experts say its complex at Yongbyon could produce several more within months.

Although the North says it has no such intention, it has quit a global nuclear nonproliferation treaty.

The North wants the United States to sign a nonaggression pact.

Deputy Secretary of State Richard Armitage on Thursday ruled out any formal treaty but said in Moscow, “We’re willing to document a no-hostile intent or so-called security guarantees for North Korea in some manner.”

Meanwhile, Undersecretary of State John Bolton arrived in Tokyo, a day after saying he had South Korea’s support and it was only “a matter of time” before the Security Council addressed the issue.

Bolton also says Britain, France and most likely Russia support U.N. consideration.

North Korea says it would consider U.N. sanctions an act of war. Bolton has said “all options are on the table,” but has not specifically recommended sanctions.

Western diplomats on the Security Council said the issue probably will not come up soon because it still is being debated by the U.N. nuclear watchdog agency in Vienna, Austria.

The push to hear the issue in the Security Council comes after Secretary of State Colin Powell said a flurry of diplomatic contacts with North Korea yielded “some progress.” Senior officials from Australia, Russia and the United Nations recently have traveled to the North.

Powell said these contacts are being used to explore ways of ending the impasse.

Russian President Vladimir Putin called President Bush on Thursday to discuss a recent visit to Pyongyang by Deputy Prime Minister Alexander Losyukov, a Kremlin press service statement said.

“The president underlined that in the opinion of the Russian side … a good basis can be seen for a productive dialogue with North Korea with the aim of … bringing the so-called ‘North Korean nuclear problem’ to a political settlement,” the Kremlin said.