They were believed to be equipped with new engines that the North tested last April, it added, when Pyongyang said they would “guarantee” an eventual nuclear strike on the US mainland.
The missiles’ existence appeared to have been intentionally leaked by Pyongyang, according to Yonhap, to send a “strategic message” to incoming US president Donald Trump, due to be sworn in on Friday.
CNN and other US news reports, quoting a US defence official, said last week that the Pentagon had deployed a high-tech sea-based X-band radar system to keep watch for a possible North Korean long-range missile launch in the coming months.
A spokesman for the South Korean military’s Joint Chiefs of Staff said the Yonhap report had not been verified.
In his closely-watched New Year speech, Kim Jong-Un said North Korea was in the “final stages” of developing an ICBM.
He said the country had significantly bolstered its nuclear deterrent in 2016, pointing to a string of nuclear and missile tests last year.
