Nuclear tensions are high again between North Korea and the United States — days after a much-welcomed cooling-off period — with renewed sabre-rattling calling out President Trump by name as the U.S. and South Korea launch joint military maneuvers today.

“The Trump group’s declaration of the reckless nuclear war exercises … is a reckless behavior driving the situation into the uncontrollable phase of a nuclear war,” the report in Rodong Sinmun read, according to CNN. The North Korean government newspaper also promised that the pariah state can at anytime target the U.S. with a “merciless strike.”

The warning — printed in an official North Korean government newspaper — came just hours before the U.S. and South Korea were slated today to start the so-called “Ulchi Freedom Guardian” military exercises, a 10-day annual military drill on the Korean peninsula.

“No one can guarantee that the exercise won’t evolve into actual fighting,” North Korea claimed in the editorial, according to a South Korean news agency.

The messages come after Pyongyang just last week said it had finalized plans to fire four missiles toward the U.S. territory of Guam, though North Korean dictator Kim Jong Un ultimately decided to hold off to “watch a little more the foolish and stupid conduct of the Yankees,” — a statement seen as backing down on the threat, possibly under pressure from China.

The new rhetoric means the chances of some type of “provocation” from North Korea — such as another missile test or perhaps a cyberattack — are “quite high,” said Sung-Yoon Lee, a professor of Korean studies at Tufts University’s Fletcher School. Shortly after last year’s exercises, for example, North Korea conducted its second nuclear missile test in nine months.

“North Korea is very good at smokescreen. They sound crazy, but they’re not crazy, they’re not irrational,” Lee said. “They’re very good at sending mixed signals before launching a major attack.”

That possibility has prompted some calls for the U.S. to scale back the military exercises. Bay State U.S. Sen. Edward J. Markey, who is currently leading a congressional delegation in Korea, China and Japan, said the U.S. should consider modifying the drills if North Korea agrees to freeze its weapons programs.

“We’re at a stage of tensions that we have not seen for years,” Markey told The Wall Street Journal yesterday. “Tensions could flare up again.”

But others say it’s likely North Korea is only using the military exercises as an excuse to act out, and, according to Lee, it could even embolden Kim to try to further bully or even blackmail the U.S. and South Korea “again and again.”

“There’s a lot we can do (through diplomacy) to bring the tension down without undermining the security of South Korea or U.S.,” said Robert S. Ross, a Boston College political science professor. “We can do these things quietly without suggesting you’re reducing our opposition to North Korea’s nuclear program.”