SEOUL, South Korea >> North Korea’s military on Tuesday greeted the start of annual U.S.-South Korean military drills with its standard fiery threats, vowing “merciless retaliation” for exercises Pyongyang claims are an invasion rehearsal.

North Korea routinely issues such warlike rhetoric or conducts weapons tests to respond to the U.S.-South Korean exercises. Tuesday’s threat came as top U.S. generals, including Adm. Harry Harris, the commander of U.S. forces in the Pacific, visited South Korea. Ties between the Koreas are almost always fraught, but anxiety is higher than normal following weeks of tit-for-tat threats between President Donald Trump and Pyongyang in the wake of the North’s two intercontinental ballistic missile tests last month.

The U.S. generals were to travel to the site of a contentious U.S. missile-defense system in South Korea later Tuesday.

The North’s military statement said it will launch an unspecified “merciless retaliation and unsparing punishment” on the United States over the Ulchi Freedom Guardian drills that began Monday for an 11-day run.

Despite the threat, an unprompted direct attack is extremely unlikely because the United States vastly outguns Pyongyang, which values the continuation of its dictatorship above all else. Impoverished North Korea hates the drills in part because they force it to respond with expensive military measures of its own.

The North Korean statement accused the United States of deploying unspecified “lethal” weapons for the drills that it says involve a “beheading operation” training aimed at removing absolute ruler Kim Jong Un.

“No one can vouch that these huge forces concentrated in South Korea will not go over to an actual war action now that the military tensions have reached an extreme pitch in the Korean Peninsula,” the statement said. “Moreover, high-ranking bosses of the U.S. imperialist aggressor forces flew into South Korea to hold a war confab. Such huddle is increasing the gravity of the situation.”

Sen. Edward Markey, a Massachusetts Democrat who visited Seoul with other lawmakers, said Tuesday that a dialogue would be the best way to defuse the North Korean nuclear standoff though he argues the United States and its allies must be ready to respond to potential aggression by North Korea with “overwhelming force.”

“Talking with North Korea is not a concession, it is the only way to reach an agreement to denuclearize the Korean Peninsula and to reinforce that our military strength is there only to deter aggression and to defend against attack,” Markey told a news conference.

Last month North Korea test-launched two ICBMs at highly lofted angles, and outside experts say those missiles can reach Alaska, Los Angeles or Chicago if fired at normal, flattened trajectories. Analysts say it will be only a matter of time for the North to achieve its long-stated goal of acquiring a nuclear missile that can strike anywhere in the United States.

Earlier this month, Trump pledged to answer North Korean aggression with “fire and fury” and later said a military solution was “locked and loaded.” North Korea, for its part, threatened to launch missiles toward the American territory of Guam before Kim Jong Un said he would first watch how Washington acts before going ahead with the missile launch plan.

The Ulchi drills are largely computer-simulated war games held every summer, and this year’s exercise involves 17,500 American troops and 50,000 South Korean soldiers.

No field training like live-fire exercises or tank maneuvering is involved in the Ulchi drills, in which alliance officers sit at computers to practice how they would engage in battles and hone their decision-making capabilities. The allies have said the drills are defensive in nature.