SEOUL, South Korea (AP) — North Korea fired two short-range ballistic missiles off its east coast Wednesday in defiance of U.N. resolutions, South Korea’s military said, less than a week after Pyongyang’s first weapons tests in more than two months.

Observers say the launches were aimed at ramping up pressure on the United States to make concessions as the two countries are struggling to resume diplomacy on the North’s nuclear weapons program.

South Korea’s Joint Chiefs of Staff said in a statement the missiles were launched from the town of Wonsan, a regular launch site on the North’s eastern coast. It said both missiles were believed to have flown about 250 kilometers (155 miles) at a maximum altitude of 30 kilometers (19 miles) and that South Korean and U.S. militaries were trying to find more details of the launches.

“The North’s repeated missile launches are not helpful to an effort to ease tensions on the Korean Peninsula and we urge (North Korea) to stop this kind of behavior,” a Joint Chiefs of Staff statement said.

Six days earlier, North Korea fired two short-range ballistic missiles that Seoul officials say flew 600 kilometers (370 miles) before landing at sea.

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U.N. Security Council resolutions ban North Korea from using ballistic technology in any weapons launches. But it’s unlikely that the nation, already under 11 rounds of U.N. sanctions, will be hit with fresh punitive measures. Past sanctions were imposed only when the North conducted long-range ballistic launches.

Japan’s Defense Minister Takeshi Iwaya told reporters Wednesday that the launched objects did not reach the Japanese exclusive economic zone and that officials are still analyzing details including the flight distance and trajectory. Referring to the previous launches, Iwaya said, “It is extremely regrettable that North Korea continues firing the missiles that violates the U.N. resolutions.”

North Korea’s state media said last week’s tests were supervised by Kim Jong Un and were designed to deliver a “solemn warning” to South Korea over its purchase of high-tech U.S.-made fighter jets and planned military drills that Pyongyang sees as an invasion rehearsal.

Wednesday’s launches came hours after a senior U.S. official said President Donald Trump has sent mementos from his brief visit to an inter-Korean border town late last month to Kim.

The official said a top staffer from the National Security Council hand-delivered photographs from the June Trump-Kim meeting at the Korean Demilitarized Zone to a North Korean official last week. The Trump administration official spoke on the condition of anonymity because the official wasn’t authorized to speak publicly.

The DMZ meeting was the third summit between Trump and Kim. At their second meeting, in Vietnam, Trump rejected Kim’s demand for widespread sanctions relief in return for dismantling his main nuclear complex, a partial disarmament step.

During the DMZ meeting, Trump and Kim agreed to resume the nuclear diplomacy in coming weeks, but there hasn’t been any known meeting between the countries. Some experts say North Korea wants a U.S. promise to ease sanctions, accept a slow, step-by-step disarmament process by North Korea or make other concessions once the diplomacy restarts.

Despite a recent lack of progress in nuclear diplomacy, both Trump and Kim have said they have maintained good relations with each other. After Thursday’s missile launches, Trump tried to downplay the significance of the tests, saying that “short-range” was the most important word. He said North Korea fired “standard” missiles many countries possess.

South Korea’s military said the flight data of the weapon launched last week 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.

After entering talks with the U.S., North Korea has suspended nuclear and long-range missile tests, and Trump views that as a proof that his North Korea policy is working well and has eased the danger of a war with the North. In 2017, Trump and Kim exchanged crude insults and threats of destruction as Kim was orchestrating a series of high-profile nuclear and missile tests as part his efforts to achieve his stated goal of acquiring nuclear missiles capable of reaching the continental U.S.

Associated Press journalists Zeke Miller in Washington and Mari Yamaguchi in Tokyo contributed to this report.