SEOUL: North Korea's Kim Yo Jong, the sister of leader Kim Jong Un, said U.S.-South Korea military drills that began this week were a "provocative and aggressive war rehearsal" that would harm regional stability, state media KCNA reported on Tuesday.

The annual Freedom Shield military exercises revealed the allies' "habitual hostile policy" toward North Korea and "will further destroy regional stability," Kim said in a statement.

Kim described the drills in South Korea as involving more than 18,000 South Korean and U.S. forces and being staged "day and night across the territorial ground, sea, air, outer space and cyberspace" of North Korea.

She said the display of military force could "lead to terrible consequences that are unimaginable."

Recent global geopolitical crises and various international events demonstrate that in all military manoeuvres carried out by hostile forces, there is no distinction between defence and offense, nor between drills and actual combat, Kim said.

South Korea and the United States have said the drills, which run from March 9 to 19, were "defensive in nature" and would incorporate deterrence scenarios related to North Korea's nuclear weapons.

The exercise will also serve as an opportunity to support ongoing preparations for the transfer of U.S. wartime operational control to South Korea, officials from both countries have said.

South Korea aims to complete the handover of military command from the U.S. before President Lee Jae Myung's term ends in 2030.

Analysts say the drills come at a sensitive time for North Korea, as it witnesses the U.S. and Israel carry out leadership‑targeting operations against Iran that may reinforce Pyongyang's reliance on its nuclear capacity.

Kim's remarks that offensive power is the most reliable deterrent "reflects a determination not to suffer the same fate as Iran, serving as both a justification for self‑defence and a renewed message at home and abroad that giving up nuclear weapons would mean doom," said Lim Eul-chul, a North Korea expert at South Korea's Kyungnam University.

The U.S.-South Korea drills follow North Korea's ruling Party Congress in February, where leader Kim Jong Un said he would focus on expanding his country's nuclear arsenal.