Barack Obama, the US president, will welcome his counterpart from South Korea for talks next month, the White House has announced.
Park Geun-hye, South Korea's newly elected president, will meet Obama in Washington on May 7, with notice of the meeting coming amid heightened tensions with North Korea.
In a statement on Monday, the White House press secretary Jay Carney noted that the US and South Korea are observing the 60th anniversary of their alliance.
Carney said both leaders would discuss the North Korean threat and efforts to denuclearise the Korean peninsula.
North Korea recently has been issuing regular threats against the US and South Korea, though a test firing of a missile that had been expected by North Korea on Monday had not occurred late in the day.
Park was elected in December and took office on February 25. She is South Korea's first female president.
North Korea's military on Tuesday threatened the South with imminent "sledge-hammer" retaliation unless Seoul apologised for anti-Pyongyang protesters burning effigies of its revered leaders.
South Korea called the North's ultimatum "regrettable" and pledged a tough response to any military provocation.
The warning came a day after the US Secretary of State John Kerry wrapped up a Northeast Asian tour aimed at defusing soaring military tensions on the Korean peninsula and getting China to help rein in a belligerent Pyongyang.
As North Korea marked the birth of late founding leader Kim Il-Sung on Monday - a major national holiday - about 40 protesters in Seoul burned portraits of Kim, his son Kim Jong-Il and grandson and current leader Kim Jong-Un.
Condemning what it described as a "thrice-cursed... monstrous criminal act", the Korean People's Army Supreme Command issued an "ultimatum" threatening "just" and immediate action if an apology was not forthcoming.
"Our retaliatory action will start without any notice," it said in a statement carried by the Korean Central News Agency.
"The military demonstration... will be powerful sledge-hammer blows at all hostile forces hurting the dignity of the supreme leadership," it added.
Al Jazeera's Harry Fawcett, reporting from Seoul, said there was, still, some hope for talks between the two Koreas.
"The South Koreans have been saying that so far, North Korean has rejected their entreaties for talks, but in this statement they [North Koreans] say, 'If the puppet authorities truly want dialogue and negotiations, for all anti-[North Korea] hostile acts," said Fawcett.
"So, potentially, in a few day's time we might see talks," said our correspondent.
Intelligence reports suggest the North has had two medium-range missiles primed to fire from its east coast for at least a week, with most observers predicting a launch around the date of Kim Il-Sung's birthday.