WASHINGTON • Russian Foreign Minister Sergei Lavrov has described the rhetoric between leaders of the United States and North Korea as a "kindergarten fight between children" and urged calm.

"We have to calm down the hotheads and understand that we do need pauses, that we do need some contacts," Mr Lavrov told a news conference last Friday at the United Nations, where he was attending the annual General Assembly debate.

In his first address to the world gathering last Tuesday, US President Donald Trump threatened to "totally destroy North Korea," derided leader Kim Jong Un as a "rocket man" and said he was on a "suicide mission".

Mr Kim shot back at Mr Trump on Thursday, describing him as "mentally deranged" and warning he would "pay dearly" for his threat.

Mr Lavrov said Russia was working with other countries "to strive for the reasonable, and not the emotional, approach - instead of the kindergarten fight between children (where) no one can stop them".

Moscow would welcome any attempt by a third country to mediate in the crisis, Mr Lavrov told a news conference, adding that this could come from a "neutral" European nation. Switzerland has offered its mediation.

Russia and China are pushing a joint proposal to kick-start talks with North Korea by freezing Pyongyang's nuclear and missile tests in exchange for a suspension of US-South Korean military drills. The US, however, has rejected that proposal as "insulting" and maintains it will not offer incentives to Pyongyang to come to the negotiating table.

Without mentioning the US, Mr Lavrov said those countries that refuse dialogue are "not fulfilling" the obligations of UN Security Council resolutions that call for a peaceful settlement to the crisis.

North Korea, in recent weeks, detonated its sixth nuclear bomb and has test-fired intercontinental missiles - saying it needs to defend itself against hostility from the US and its allies.

Mr Lavrov also said he rejected the idea of reopening negotiations on the Iran nuclear deal, insisting that US concerns about Teheran's behaviour can be addressed outside the agreement.

He added that a collapse of the Iran nuclear deal would give North Korea little incentive to drop its nuclear programme in return for sanctions relief.

AGENCE FRANCE-PRESSE, REUTERS