SEOUL - U.S. President Donald Trump has sent a happy birthday message to North Korean leader Kim Jong Un, who is believed to have turned 36 Wednesday. It is the first recent reported contact between the two leaders amid stalled nuclear talks.

Trump asked that South Korea deliver the birthday message to Kim, according to South Korea’s national security adviser, Chung Eui-yong, who met briefly with Trump this week in Washington.

Chung, who spoke with reporters at the airport after returning to Seoul Friday, said he believed the message was delivered through “proper channels.” It is not clear what else, if anything, was in Trump’s message, what form the message took, or how it was delivered.

Trump and Kim have exchanged personal letters during nearly two years of diplomacy. Trump has hinted the two also talk on the phone. Trump insisted last week the relationship remains “very good,” despite U.S.-North Korea talks being stalled.

In his New Year’s comments, Kim vowed the world would witness an unspecified “new strategic weapon in the near future.” Kim also said he no longer felt bound by his self-imposed suspension of long-range missile and nuclear tests.

Kim did not, however, announce a formal end to negotiations, and North Korea has not delivered its threatened “Christmas gift” to the U.S., which many analysts guessed could be a weapons test.

“He likes me. I like him. We get along,” Trump said last week. “He’s representing his country. I’m representing my country. We have to do what we have to do.”

“And I think he’s a man of his word. So we’re going to find out,” Trump added.

The talks have not progressed since February, when Trump and Kim were unable to reach a deal at a summit in Hanoi. Kim later set an end-of-year deadline for the U.S. to offer more concessions and subsequently tested 13 rounds of short-range missiles and artillery. It’s not yet clear what Kim may do to enforce the deadline.

For now, North Korea may look to benefit from maintaining a low-key profile, said Duyeon Kim, a senior adviser for Northeast Asia and nuclear policy at the International Crisis Group.

“It can continue to advance toward its nuclear and economic goals without ruffling Trump’s feathers,” she wrote in the Bulletin of Atomic Scientists.

Many analysts are pessimistic about the short-term chances for talks, though, given Kim’s New Year’s comments about a long-term standoff with the U.S.

“North Korea has made clear it will not return to the talks unless the U.S. offers new proposals,” Kim Dong Yub, a North Korea expert at Kyungnam University's Institute for Far Eastern Studies, said at a conference in Seoul on Friday.

The North Korean leader has not likely abandoned talks altogether, however, Kim said. “The U.S. is the only country that can help North Korea be a normal nation in the international community,” he added.

Although the birthdays of Kim's father and grandfather, Kim Jong Il and Kim Il Sung, are celebrated as major national holidays in North Korea, the younger Kim’s birthday is not yet observed.

There were no reported celebrations in North Korea and state media did not mention the birthday. North Korea has not revealed Kim’s age, but South Korean and U.S. officials believe he is 36.