North Korea says it has successfully tested a solid-fuel rocket engine, which would be a major step in its effort to develop a long-range missile able to reach South Korea and the United States.
The North's state-run Korean Central News Agency says leader Kim Jong-un was on hand for the test, which he said "will strike great horror and terror into the hearts of the enemies."
Using solid-fuel reduces the amount of launch preparation time, increases the mobility of the missiles, and makes them far more reliable than liquid-fueled rockets.
Pyongyang has made similar claims before of progress in its nuclear weapons and ballistic missile programs, including a successful simulation of an atmospheric re-entry of a ballistic missile. Multiple defense experts South Korea and abroad have expressed doubts that North Korea has developed a long-range ballistic missile, or a vehicle that can withstand the searing heat of re-entry into the Earth's atmosphere.
Thursday's claim by the North is the regime's latest response to the annual joint U.S.-South Korea military drill, and a new, stronger round of sanctions imposed by the United Nations over Pyongyang's recent nuclear and ballistic missile tests. North Korea has threatened to launch a massive military attack against Seoul, and launched several short and medium-range rockets and projectiles in the past week.
South Korean President Park Geun-hye on Thursday ordered a heightened security posture to cope with a potential North Korean provocation.
Chinese Vice Foreign Minister Li Baodong told reporters Thursday that President Xi Jinping will discuss the North Korean nuclear situation with U.S. President Barack Obama on the sidelines of a nuclear security summit in Washington next week.
Beijing and Washington are two members of six-party talks aimed at curbing Pyongyang's nuclear weapons program, along with Japan, Russia and the two Koreas. The talks broke down in 2008.