SEOUL, South Korea - North Korea said Tuesday that it doesn't oppose resuming dialogue with the U.S. in its first conciliatory gesture after months of threats to attack South Korea and American bases and warnings of pre-emptive nuclear strikes.

The offer is predicated on receiving U.S. assurances that it isn't trying to provoke a nuclear war, an unidentified Foreign Ministry spokesman said in a statement on the official Korean Central News Agency. This came less than a day after North Korea threatened to attack South Korea at any time.

North Korea has repeatedly said the region is on the brink of war since testing a nuclear weapon in February in defiance of United Nations sanctions.

President Obama said North Korea probably isn't able to launch a nuclear-tipped missile.

"Based on our current intelligence assessments, we do not think that they have that capacity," Obama said in a recorded interview broadcast Tuesday morning on NBC's "Today" show. Even so, he said, "we have to make sure we are dealing with every contingency out there."

Obama said the U.S. has repositioned missile defenses "to guard against any miscalculation on their part" and that he expected North Korea to "make more provocative moves over the next several weeks."

"We're not going to reward this kind of provocative behavior," he said. "You don't get to bang your spoon on the table and, somehow, you get your way."

A U.S. military official earlier said that North Korean leader Kim Jong Un's inexperience raises the risk of miscalculation.

While a missile or nuclear weapons test remains possible given the hostile rhetoric from the totalitarian state over the past several weeks, there are no signs North Korean forces are mobilizing, the official told reporters in Seoul. The comments came hours after the comment from Kim's military that a strike on South Korea could come at any time.

North Korea for a second day commemorated the April 15 birthday of state founder Kim Il Sung - the current leader's grandfather - as both the U.S. and South Korea said they are willing to return to negotiations.

"North Korea right now seems to be weighing whether it's more beneficial to restart talks with the U.S. or South Korea," said Hahm Hyeong-pil, an analyst at the Korea Institute for Defense Analyses in Seoul. "If they want to appeal to the U.S., then the North will continue to escalate tensions with more threats, and if it chooses the South, then it will not fire a missile."

North Korea's military on Tuesday issued "an ultimatum" to the South, saying "retaliatory action" would be aimed at those involved in instigating protests in Seoul where portraits of Kim Il Sung were set on fire, according to the official Korean Central News Agency.