PALM BEACH, Fla. — The Trump White House is reacting skeptically in private to North Korea’s announcement of plans to freeze nuclear weapons testing, warning that dictator Kim Jong Un could be setting a trap and vowing not to back off a hard-line stance ahead of a potential leaders’ summit.

President Trump called Pyongyang’s move “progress” and “good news” in a pair of tweets after the news broke Friday. Behind the scenes, however, his aides cautioned Saturday that Kim’s statement that the North would halt testing and shutter one nuclear facility was more notable for what he left out: a direct pledge to work toward nuclear disarmament.

Although some foreign policy analysts were heartened that Kim appeared eager to set a positive tone for his summit with Trump, which could come in late May or early June, Trump aides were less enthused. In their view, Kim’s moves aimed to offer relatively modest pledges – which could quickly be reversed – to create the “illusion” that he is “reasonable” and willing to compromise.

That, the Trump aides said, would make it more politically difficult for the United States to reject the North’s demands.

Kim’s announcement early Saturday in Pyongyang surprised White House officials who had been anticipating him making some sort of statement to the North Korean people in advance of a summit with Trump but did not know when or how he would deliver it.

North Korea’s state news agency read Kim’s statement on television and issued a written version in English. The young dictator pledged to turn his regime’s attention away from weapons development and toward boosting the economy on an “upward spiral.”

White House aides viewed the statement as a signal that Kim’s goal is to get the United States and its allies to ease the punishing economic sanctions that the Trump administration helped enact since the president took office.

But they vowed that the administration has learned from past mistakes in which North Korea violated agreements over its nuclear program after sanctions were lifted.

Kim is due to meet with South Korean President Moon Jae-in this week in what is being viewed as a preliminary summit ahead of the face-to-face with Trump. A date and location have not been announced for the latter summit.

South Korean officials said that Kim has signaled he is willing to discuss ways to formally end the Korean War, whose hostilities have been suspended since a 1953 armistice, and that he has dropped the North’s long-standing demands that the United States withdraw tens of thousands of troops stationed on the peninsula.

A key test for Trump will be to navigate the competing pressures of the U.S. allies in the region. Moon’s liberal administration is trying to broker a deal to reduce tensions over fears of war, while conservative Japanese Prime Minister Shinzo Abe, who views Kim’s recent moves more suspiciously, is pressing Trump to ensure that Japan’s interests are protected in any final agreement.

Abe used his two-day visit to Mar-a-Lago, the president’s winter retreat, to emphasize that Japan will insist on “complete, verifiable and irreversible” steps toward denuclearization. The Trump administration also has taken a similar position, raising the question of whether anything that falls short of such an agreement at a summit would be a failure.

Some Washington-based analysts said Saturday that a more realistic path for Trump would be to tacitly acknowledge that the North, after relentlessly developing its arsenal for three decades, will not take immediate, concrete steps to eliminate the program.

Another option, they suggested, would be to move first to enact constraints on the North’s arsenal, such as capping the program with limits to contain the threat. This would allow the North the security of maintaining some level of nuclear proficiency while enacting curbs on key bomb fuels and delivery systems.