The country plans to deploy 40 of the American jets by the end of 2021, with around a quarter of those expected to be operational this year.
South Korean authorities “know well that the bringing-in of the Fighters would prove to be an extremely dangerous action which will trigger our reaction,” an unnamed researcher at the Institute for American Studies of North Korea’s Ministry of Foreign Affairs said in a statement carried by state news agency KCNA.
“We… have no other choice but to develop and test the special armaments to completely destroy the lethal weapons reinforced in South Korea,” it said.
The statement said that two more F-35As were due to be delivered to South Korea from the US in mid-July. Seoul’s defence ministry declined to comment on whether this was the case.
The two neighbours are technically still at war after the 1950-53 Korean War ended with a ceasefire instead of a peace treaty.
Tensions were raised in May when North Korea fired short-range missiles for the first time since November 2017, during a standstill in its talks with Washington over denuclearisation.
Nuclear-armed Pyongyang has criticised Seoul for not pursuing inter-Korean economic projects as discussed in summit meetings between North Korean leader Kim Jong Un and South Korean President Moon Jae-in last year.
Several sets of sanctions, imposed on the North over its nuclear and ballistic missile programmes, currently block many proposed developments in sectors from industry to tourism.
© Agence France-Presse