North Korea branded South Korean President Moon Jae-in a "parrot raised by America" in a statement published by state media on Tuesday.

Kim Yo Jong, the sister of North Korean leader Kim Jong Un said that Moon's "illogical and brazen faced" criticism of missile tests echoed the US stance. 

Seoul's Unification Ministry expressed "strong regret" over Jong's statement, saying that the two countries must observe "the rules of minimum etiquette in any circumstance."

What did Moon say about the missile tests? 

North Korea fired two "new-type tactical guided missiles" into the sea on Thursday. Moon said "actions providing difficulty for the mood for dialogue are undesirable," according to the news agency Yonhap.

The South Korean president added that "people are greatly concerned" by North Korea's missile launches. The criticism was similar to comments made by US President Joe Biden, who pledged a response if the North continued to escalate tensions. 

A UN Security Council resolution has banned missile and nuclear tests by North Korea, which they say pose a threat to international peace. North Korea argues it has sovereign rights to perform such tests to help counter US military threats.

Who is Kim Yo Jong?

The North Korean leader's powerful sister was once considered a possible predecessor to Kim Jong Un among rumours of his poor health.

Jong had visited Seoul in early 2018 and conveyed her brother's invitation to President Moon to visit Pyongyang.

But since relations strained again later, she has shifted her image from peace messenger to leading anti-Seoul figure

jm/rt (AP, dpa)