SEOUL, Korea, Republic Of -- North Korea's test of a new missile is meant as a "solemn warning" over rival South Korea's weapons development and plans to hold military drills with the United States, Pyongyang said Friday as it continued its pressure campaign ahead of potential nuclear talks.

South Korea's military later said that the flight data of the weapon launched Thursday showed similarities to the Russian-made Iskander, a short-range, nuclear-capable missile. A North Korean version could likely reach all of South Korea -- and the 28,500 U.S. forces stationed there -- and would be extremely hard to intercept.

The North Korean statement was carried in state media and directed at "South Korean military warmongers." It appears to be part of broader efforts during recent weeks to make sure Pyongyang gets what it wants as U.S. and North Korean officials struggle to set up working-level talks after a recent meeting on the Korean border between North Korean leader Kim Jong Un, who supervised Thursday's test launch, and President Donald Trump seemed to provide a step forward in stalled nuclear negotiations.

Although the North had harsh words for South Korea, the statement stayed away from the kind of belligerent attacks on the United States that have marked past announcements, a possible signal that it's interested in keeping diplomacy alive.

It made clear, however, that North Korea is infuriated over Seoul's purchase of U.S.-made high-tech fighter jets and U.S.-South Korean plans to hold military drills this summer that the North says are rehearsals for an invasion and proof of the allies' hostility to Pyongyang.

U.S. Secretary of State Mike Pompeo played down Thursday's launches and said in an interview with Bloomberg TV that working-level talks with North Korea could start "in a couple weeks."

"Everybody tries to get ready for negotiations and create leverage and create risk for the other side," Pompeo said of the launches.

The North Korean statement was gloating at times, saying the weapons test "must have given uneasiness and agony to some targeted forces enough as it intended." It also accused South Korea of introducing "ultramodern offensive weapons."

That's likely a reference to South Korea's purchase and ongoing deployment of U.S.-made F-35 fighter jets. Earlier this month, North Korea said it would develop and test "special weapons" to destroy the aircraft. In its biggest weapons purchase, South Korea is to buy 40 F-35 fighter jets from Lockheed Martin by 2021. The first two arrived in March and two others are to be delivered in coming weeks.

After watching the launches, Kim said the new weapons are hard to intercept because of their "low-altitude gliding and leaping flight orbit," the North's Korean Central News Agency reported Friday. He was quoted as saying the possession of "such a state-of-the-art weaponry system" is of "huge eventful significance" in bolstering his country's armed forces and guaranteeing national security.

A joint South Korean-U.S. analysis of the launches showed the North Korean weapons are of a new type of short-range ballistic missile that have a "similar flight feature" as the Iskander, which has been in the Russian arsenal for more than a decade, a South Korean defence official said, requesting anonymity because of department rules.

That missile is designed to fly at a flattened-out altitude of around 40 kilometres and make in-flight guidance adjustments. Both capabilities exploit weaknesses in the U.S. and South Korean missile defences that are now in place, primarily Patriot missile batteries and the THAAD anti-missile defence system. The Iskander is also quicker to launch and harder to destroy on the ground, because of its solid fuel engine. Its advanced guidance system also makes it more accurate.

The South Korean defence official said both missiles flew 600 kilometres before landing off the North's east coast, revising an earlier estimate that one flew about 430 kilometres and the other 690 kilometres.

Earlier Friday, the South Korean-U.S. combined forces command issued a statement saying the launches "were not a threat directed at (South Korea) or the U.S., and have no impact on our defence posture."

The launches were the first known weapons tests by North Korea since it fired three missiles into the sea in early May that many outside experts said strongly resembled the Iskander.

South Korea's Unification Ministry on Friday described the launches as provocative acts "not helpful to efforts to alleviate military tensions on the Korean Peninsula."

In Washington, State Department spokeswoman Morgan Ortagus urged the North to stop provocations, saying the United States is committed to diplomatic engagement with North Korea. "We continue to press and hope for these working-level negotiations to move forward," she said.

North Korea is banned by UN Security Council resolutions from engaging in any launch using ballistic technology. While the North could face international condemnation over the latest launches, it's unlikely that the nation, already under 11 rounds of UN sanctions, will be hit with fresh punitive measures. The UN council has typically imposed new sanctions only when the North conducted long-range ballistic launches.

Annual military drills by Washington and Seoul have long been a source of frustration for North Korea. Last week, it said it may lift its 20-month suspension of nuclear and long-range missile tests in response. Seoul said Wednesday that North Korea was protesting the drills by refusing to accept its offer to send 50,000 tons of rice through an international agency.

North Korea also may be trying to get an upper hand ahead of a possible resumption of nuclear talks. Pyongyang wants widespread sanctions relief so it can revive its dilapidated economy. But U.S. officials demand North Korea first take significant steps toward disarmament before they will relinquish the leverage provided by the sanctions.

"North Korea appears to be thinking its diplomacy with the U.S. isn't proceeding in a way that they want. So they've fired missiles to get the table to turn in their favour," said analyst Kim Dae-young at the Korea Research Institute for National Strategy.

------

Klug reported from Tokyo