TOKYO — North Korea’s state media released photos Wednesday that appear to show the designs of one or possibly two new missiles.
Concept diagrams of the missiles were seen hanging on a wall behind leader Kim Jong Un while he visited a plant that makes solid-fuel engines for the country’s ballistic-missile program.
One of the photos clearly showed a diagram for a missile called Pukguksong-3, which appears to be the latest in its Pukguksong, or Polaris, series.
The other was harder to discern, though it carried a Hwasong, or Mars, designation name.
The photos were carried in the morning edition of the Rodong Sinmun, the ruling party’s newspaper, and released by the Korean Central News Agency just two days after the United States and South Korea began annual military exercises that the North claims are a rehearsal for war.
Tensions on the peninsula generally ratchet up during the maneuvers and a series of larger exercises held each spring.
The KCNA report on the visit said Kim called on workers at the plant to produce more solid-fuel rocket engines and rocket warhead tips.
Michael Duitsman, a research associate at the Center for Non-Proliferation Studies, said the first missile has not been seen before.
‘‘The Pukguksong-3 is definitely new,’’ he said in an e-mail to the AP.
The missile might be designed to fly farther and to be launched from protective canisters, which allow missiles to be transported more easily and make them more difficult to locate and destroy in advance. Solid-fuel engines add to that difficulty because they allow for quicker launches than liquid-fuel missiles. It could possibly also boost the North’s submarine-launched missile capabilities.
Meanwhile, China on Wednesday urged the United States to withdraw new sanctions it imposed on Chinese companies that Washington says are supporting North Korea as it carries out increasingly ambitious missile tests.
On Tuesday, the Trump administration imposed sanctions on 16 mainly Chinese and Russian companies and people for assisting North Korea’s nuclear and ballistic missile programs and helping it to make money to support those programs.
Chinese foreign ministry spokeswoman Hua Chunying told reporters at a regular briefing that China opposes unilateral sanctions and ‘‘the long-arm jurisdiction taken’’ by the United States against Chinese entities and individuals.