North Korean leader Kim Jong Un. Photograph:( Reuters )
The United States has placed sanctions on two North Koreans who it says are part of the country's nuclear missile programme, while Russia has reiterated its offer to mediate between the two countries.
The two men have been identified as Kim Jong-sik and Ri Pyong-chol. The US said Kim was part of North Korea's efforts to switch its missile program from liquid to solid fuel, while Ri was part of its ICBM (intercontinental ballistic missile) development programme.
The two men have often been seen photographed with North Korean leader Kim Jong-un at missile launches.
"Treasury is targeting leaders of North Korea’s ballistic missile programs, as part of our maximum pressure campaign to isolate (North Korea) and achieve a fully denuclearized Korean Peninsula,” US Treasury Secretary Steven Mnuchin said in a statement.
The sanctions will allow the US to block any property or interests the two North Korean men might have in US jurisdiction and stop any further dealings with US citizens.
The UN had on Friday imposed new sanctions on North Korea in response to its ICMB test conducted last month, which Pyongyang said put all of the US mainland within range of its nuclear weapons.
The UN sanctions limit North Korea's access to refined petroleum products and crude oil as well as its earning from workers overseas.
North Korea said the move was "an act of war" and equivalent to a total economic blockade.
The two North Koreans sanctioned by the US, along with weapons developer Jang Chan-ha, were reportedly personally selected by Kim Jong-un and were popular with him.
Pyong-chol is an ex-air force general who studied in Russia, and Jong-sik is a veteran rocket scientist.
On Tuesday, the Kremlin, which has long called for the two sides to hold negotiations, said it was ready to act as a mediator if the United States and North Korea were willing for it to play such a role.
"Russia's readiness to clear the way for de-escalation is obvious," Kremlin spokesman Dmitry Peskov told reporters.
Asked to comment on the offer, a spokesman for the U.S. State Department, Justin Higgins, said the United States "has the ability to communicate with North Korea through a variety of diplomatic channels," and added:
"We want the North Korean regime to understand that there is a different path that it can choose, however it is up to North Korea to change course and return to credible negotiations."
(With inputs from agencies)