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SEOUL, South Korea — North Korea said a nuclear war on the Korean Peninsula has become a matter of when, not if, as it continued to lash out at a massive joint military exercise between the United States and South Korea involving hundreds of advanced warplanes.

In comments attributed to an unnamed Foreign Ministry spokesman, North Korea also claimed high-ranking U.S. officials, including CIA Director Mike Pompeo, have further confirmed American intent for war with a series of "bellicose remarks."

Pompeo said Saturday that U.S. intelligence agencies believe North Korean leader Kim Jong Un doesn't have a good idea about how tenuous his situation is domestically and internationally. The North's spokesman said Pompeo provoked the country by "impudently criticizing our supreme leadership which is the heart of our people."

"The large-scale nuclear war exercises conducted by the U.S. in succession are creating touch-and-go situation on the Korean Peninsula and series of violent war remarks coming from the U.S. high-level politicians amid such circumstances have made an outbreak of war on the Korean Peninsula an established fact. The remaining question now is: when will the war break out," the spokesman said.

"We do not wish for a war but shall not hide from it, and should the U.S. miscalculate our patience and light the fuse for a nuclear war, we will surely make the U.S. dearly pay the consequences with our mighty nuclear force which we have consistently strengthened."

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The comments were carried by the official Korean Central News Agency late Wednesday, hours after the United States flew a B-1B supersonic bomber over South Korea as part of a massive combined aerial exercise involving hundreds of warplanes.

South Korea's Joint Chiefs of Staff said the Guam-based bomber simulated land strikes at a military field near South Korea's eastern coast during a drill with U.S. and South Korean fighter jets.

"Through the drill, the South Korean and U.S. air forces displayed the allies' strong intent and ability to punish North Korea when threatened by nuclear weapons and missiles," the South Korean military said in a statement.

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B-1B flyovers have become an increasingly familiar show of force to North Korea, which after three intercontinental ballistic missile tests has clearly moved closer toward building a nuclear arsenal that could viably target the U.S. mainland.

The five-day drills that began Monday involve more than 200 aircraft, including six U.S. F-22 and 18 F-35 stealth fighters.

North Korea hates such displays of American military might at close range and typically uses strong language to condemn them as invasion rehearsals. It has been particularly sensitive about B-1B bombers, describing them as "nuclear strategic" although the planes were switched to conventional weaponry in the mid-1990s.

China, North Korea's neighbor and lone major ally, again urged calm and said war was not the answer.

"We hope all relevant parties can maintain calm and restraint and take steps to alleviate tensions and not provoke each other," Chinese Foreign Ministry spokesman Geng Shuang said in a statement. "The outbreak of war is not in any side's interest. The ones that will suffer the most are ordinary people."

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Tensions on the Korean Peninsula have risen markedly in recent months after North Korea's latest missile and nuclear tests, conducted in defiance of U.N. Security Council resolutions and international condemnation.

North Korea regularly threatens to destroy South Korea and the United States and says its weapons program are necessary to counter American aggression. The United States stations 28,500 troops in the South.

North Korea has said in public statements that it wants an official end to the Korean War. The conflict was halted by a 1953 armistice but no peace treaty has been signed. It also wants nothing short of full normalization of relations with the U.S. and to be treated with respect and as an equal in the global arena.