Updated

The interception of a U.S. reconnaissance plane by North Korean fighter jets heightens tension on the Korean Peninsula amid fears that the North could make nuclear bombs within months.

Lt. Cmdr. Jeff Davis, a Pentagon spokesman, said four North Korean fighter jets approached the U.S. plane over the Sea of Japan on Sunday, coming as close as 50 feet. One used its radar to identify the plane as a target, but there was no hostile fire, he said.

Davis said it was the first such incident since April 1969 when a North Korean plane shot down a U.S. Navy EC-121 surveillance plane, killing all 31 Americans aboard.

In an interview with 14 U.S. newspapers, President Bush repeated the U.S. stance that the situation can be resolved with diplomacy. According to The Baltimore Sun, Bush said that while the military option has not been taken off the table, it would be a last resort in dealing with the country's moves toward nuclear weapons production.

Asked how successful diplomatic efforts have been, Bush said: "It's in process. If they don't work diplomatically, they'll have to work militarily. And military option is our last choice. Options are on the table, but I believe we can deal with this diplomatically. I truly do."

The interception fit a pattern of recent North Korean actions that could be an effort to pressure the United States into negotiations on chief Northern aims: a nonaggression treaty and aid for its dilapidated economy.

"Ever since the nuclear issue surfaced, North Korea has been taking steps to increase tension and to show its hostility," said Lee Suk-soo, a military studies professor at the National Defense College in Seoul.

"The reckless move is a signal to the United States at a time when Washington pays little attention to North Korea's repeated demand for direct dialogue," he said.

North Korea did not comment on the plane incident. Its state-run media instead criticized annual U.S.-South Korean military exercises that began Tuesday, saying they were preparation for an attack. The "Foal Eagle" exercise, which has been held since 1961, ends April 2.

"This Foal Eagle exercise is escalating the danger of armed clashes on the Korean Peninsula," said Minju Joson, a North Korean newspaper.

"If the eagle swoops down on us, a nuclear war will break out and it is clear that the whole Korean nation will not escape nuclear holocaust," said the report, which was monitored by South Korea's Yonhap news agency.

U.S. military officials say the annual maneuver is "defense-oriented" and is not related to the nuclear dispute.

Washington, which is preparing for a possible war against Iraq, says it will not be blackmailed into concessions and that North Korea's efforts to develop nuclear weapons are a multilateral issue. The U.N. Security Council is expected to debate the matter.

North Korea test-fired a missile into the sea off its east coast on the eve of South Korean President Roh Moo-hyun's inauguration last week.

On Feb. 20, a North Korean MiG-19 warplane crossed over the South's western sea border, but quickly retreated after South Korean jets flew to the area.

Last week, U.S. officials said North Korea had restarted a nuclear reactor that is at the center of a suspected weapons program. The 5-megawatt reactor could yield enough plutonium for an atomic bomb in about a year, experts say.

North Korea, which has warned that a U.S. attack on its nuclear facilities at Yongbyon would trigger war, could also decide to reactivate a reprocessing facility near the reactor. Such a move could allow it to make several nuclear bombs within months, according to defense analysts.

The United States believes the North already has one or two nuclear bombs.

In the Sunday incident, Davis said, the four North Korean planes "shadowed" the unarmed American plane over international waters for about 20 minutes before breaking off.

Two North Korean MiG-29 fighters and two other aircraft that Davis said appeared to be MiG-23 fighters intercepted the U.S. Air Force RC-135S reconnaissance plane, which Davis said was about 150 miles off North Korea's coast.

The closest the fighters came was about 50 feet, Davis said. He did not know how many crew members were aboard the RC-135, although the standard number is 17, including two pilots.

The U.S. plane broke off its mission and returned to its home station at Kadena Air Base in Japan, Davis said.

North Korean complaints about reconnaissance flights by U.S. planes had grown more frequent before the incident. On Saturday, the North said a U.S. RC-135 reconnaissance plane had intruded into its airspace off the east coast daily for a week. RC-135 planes are modified Boeing 707s.

The type of plane that was intercepted, nicknamed "Cobra Ball," is loaded with electronic receivers and features large circular windows in the fuselage for the photography of foreign ballistic-missile tests at long range.

The current nuclear dispute began in October when U.S. officials said the North acknowledged it had a secret nuclear program in violation of a 1994 agreement.

Washington and its allies suspended oil shipments, which were part of the agreement, and North Korea responded by moving to reactivate frozen nuclear facilities and withdrawing from the Nuclear Nonproliferation Treaty.