North Korea is sending mixed signals to the South. On Wednesday, Pyongyang conveyed to Seoul its condolences over the tragic sinking of a South Korean ferry through its Red Cross Society.

The North’s Red Cross chief sent a telephone message of sympathy to his counterpart in the South, expressing his deep sorrow over the disaster that claimed many casualties, including young students.

The North’s condolences are the first of their kind since 2003, when the South was hit by typhoon Maemi and a subway fire.

Pyongyang’s unexpected move followed reports of heightened activity at the North’s underground nuclear test site, which was interpreted as signaling that the North was preparing to conduct its threatened fourth nuclear test in time for U.S. President Barack Obama’s visit to the South on Friday.

Late last month, the North’s Foreign Ministry issued a statement warning that it would conduct a “new form” of nuclear test, following the U.N.’s condemnation of its earlier ballistic missile launches.

On Tuesday, the spokesman for Seoul’s Defense Ministry, referring to the increased activity at the test site, said the North appeared to be ready to undertake a nuclear test at any time it desired.

He also said that North Korean officials recently warned that “something unimaginable” would take place before April 30 as the North was preparing “something big” for its enemies.

The Defense Ministry’s intelligence led President Park Geun-hye to call Chinese President Xi Jinping on Wednesday, asking him to use China’s leverage to prevent the North from conducting another atomic bomb test.

Xi told Park that China had been doing its best to help maintain peace and stability on the Korean Peninsula. He also noted that China, like Korea, has consistently opposed a nuclear North Korea.

The North’s condolences came hours after the talks between the two leaders over the phone. Together with the condolences, the North’s Committee for the Peaceful Reunification of Korea sent to the South an open letter listing 10 demands, including the lifting of the South’s sanctions against the North.

How should the condolences be interpreted? Some North Korea watchers here view them as indicating the North’s intention to improve inter-Korean ties. If this interpretation is correct, the North’s young leader might have decided not to carry out a fourth nuclear test, at least for the time being. Otherwise, he would not have made such a conciliatory gesture.

The young leader is seen as more calculative than his father. For him, it would not have been difficult to realize that a fourth test would do his regime more harm than good. We hope he can think harder and make the strategic decision of giving up nuclear weapons and opening up the North Korean economy.