North Korean leader's sister repeats 'critical' warnings over U.S. spy planes

SEOUL, July 11 (UPI) -- Kim Yo Jong, the powerful sister of North Korean leader Kim Jong Un, repeated accusations Tuesday that U.S. spy planes crossed into the North's territory and warned of a "very critical flight" in case of "repeated illegal intrusion."

The statement, carried by the state-run Korean Central News Agency, was the latest in a brewing back-and-forth over the alleged reconnaissance flights.

On Monday night, Kim Yo Jong claimed that a U.S. spy plane repeatedly flew over the waters of the North's exclusive economic zone before being chased off by North Korean warplanes. She warned in a statement that a "shocking incident would occur" if the United States continued its reconnaissance activities in the area.

Earlier that day, a North Korean Defense Ministry spokesperson accused Washington of conducting "provocative aerial espionage" during the first week of July and threatened to shoot down American aircraft.

South Korea's Joint Chiefs of Staff denied all allegations.

In a message sent to reporters Tuesday, the JCS said the North was "intentionally creating tension through threatening words and actions" and urged it to drop the issue.

"We sternly warn that North Korea is responsible for all consequences resulting from its actions regarding the South Korea-U.S. alliance's normal flight activities," the JCS said.

The Pentagon called the North's claims "just accusations."

"The United States, as always, remains committed to safely and responsibly flying, sailing, operating anywhere that international law allows and alongside our allies and partners," Pentagon spokeswoman Sabrina Singh said during a press briefing Monday.

U.S. State Department spokesman Matthew Miller also urged the North to "refrain from escalatory actions," and called on it to "engage in serious and sustained diplomacy."

In her statement Tuesday, Kim Yo Jong said the U.S. reconnaissance plane flew over the North's exclusive economic zone waters eight times on Monday from 5:15 a.m. through 1:10 p.m., in an area some 170 miles southeast of the east coast county of Uljin.

"In case of repeated illegal intrusion, the U.S. forces will experience a very critical flight," Kim said.

She also warned that "the military gangsters of the 'ROK' should stop acting impudently and shut up at once."

The Republic of Korea is the official name of South Korea.

The heated rhetoric comes during a sustained period of military tension on the Korean Peninsula, with North Korea conducting a spate of weapons tests and the United States and South Korea ramping up their joint military exercises.

Pyongyang recently attempted to deploy its first military reconnaissance satellite, citing a need to respond to the "undisguised military threat" of U.S. and South Korean forces.

The rocket carrying the satellite crashed into the Yellow Sea shortly after launch on May 31 due to a second-stage engine failure.

Last week, the allies conducted a joint air drill involving at least one U.S. B-52H strategic bomber, while a U.S. nuclear-powered guided-missile submarine made a port call in Busan in June, the first visit of its kind in six years.