State media reported that DPRK leader Kim Jong Un's sister has called South Korea's President and government "idiots" and a "faithful dog" of the United States.

Kim Yo Jong's statement comes after Seoul said this week it was considering new unilateral sanctions against DPRK in response to recent missile tests, including an intercontinental ballistic missile launch last week.

"This disgusting act shows more clearly that the south Korean group is a 'faithful dog' and stooge of the US," Kim said in a statement carried out by the Korean Central News Agency (KCNA).

Read next: US, allies testing Pyongyang's patience: Ryabkov

"I wonder what 'sanctions' the south Korean group, no more than a running wild dog on a bone given by the US, impudently impose on the DPRK," she said. "What a spectacle sight!"

Read next: DPRK responds to South Korea, US "provocations"

Kim accused South Korean President Yoon Suk Yeol of creating a "dangerous situation", comparing him to his more dovish predecessor Moon Jae-in.

"I wonder why the south Korean people still remain a passive onlooker to such acts of the 'government' of Yoon Suk Yeol and other idiots," she said. 

DPRK to initiate new test

DPRK, according to Professor Yang Moo Jin of the University of North Korean Studies in Seoul, tends to issue statements before carrying out a "provocation", adding, "There may be an armed demonstration against South Korea and the United States soon."

Friday's ICBM launch was the latest in a string of record-breaking Pyongyang launches, which officials and analysts in Seoul and Washington have warned could lead to a seventh nuclear test.

Read next: DPRK launches ICBM, could reach US on different trajectory: Japan