A medium-range ballistic missile fired Wednesday by North Korea flew about 620 miles and landed near Japan's territorial waters, Seoul and Tokyo officials said, the longest launch by one of the North's weapons.

The U.S. Strategic Command, meanwhile, said North Korea fired two presumed Rodong missiles simultaneously on Wednesday, not the one. The command's statement said initial indications reveal one of the missiles exploded immediately after launch, while the second was tracked over North Korea and into the Sea of Japan.

According to the South Korean and Japanese announcements, one suspected Rodong missile lifted off from the North's western Hwanghae province and flew across the country before falling in waters between the Korean Peninsula and Japan.

Seoul's Joint Chiefs of Staff said in a statement that it "strongly condemns" the missile launch because it explicitly shows the North's intentions of being able to launch missile attacks on South Korea and neighboring countries.

Japan's Defense Ministry said the missile landed inside Japan's exclusive economic zone, the 200-nautical-mile offshore area where a nation has sovereign rights for exploring and exploiting resources. "It imposes a serious threat to Japan's security and it is unforgivable act of violence toward Japan's security," Prime Minister Shinzo Abe said.

North Korea previously fired Rodong and other missiles into the sea but South Korean analysts say Wednesday's flight was one of the longest for a North Korean test.

In June, North Korea, after a string of failures, sent a mid-range ballistic missile more than 870 miles high. Analysts say the high-altitude flight meant North Korea had made progress in its push to be able to strike U.S. forces throughout the region.

North Korea routinely conducts missile and other weapons tests, but the latest launch came after North Korea warned of unspecified "physical counter-actions" against a U.S. plan to deploy an advanced missile defense system in South Korea by the end of next year.

Seoul and Washington officials said they need the Terminal High-Altitude Area Defense, or THAAD, system to better cope with what they call North Korea's increasing military threats. North Korea called the system a provocation that it says is only aimed at bolstering U.S. military hegemony in the region.

On July 19, North Korea fired three ballistic missiles into the sea, according to Seoul defense officials. The North's state media later confirmed that it fired ballistic rockets carrying trigger devices for nuclear warheads as part of simulated pre-emptive atomic attacks on South Korea.

North Korea is expected to carry out more weapons launches in coming weeks to protest annual U.S.-South Korean military drills that begin later this month. North Korea describes the drills as an invasion rehearsal.

North Korea is pushing to manufacture a warhead small enough to be placed on a long-range missile that can reach the continental U.S., but South Korean defense officials say the North doesn't yet have such a miniaturized warhead. Some civilian experts, however, believe the North has the technology to put warheads on shorter-range missiles that can strike South Korea and Japan.