Referring to North Korea, he remained downbeat about the current United States and South Korean leaders' ability to resolve what he described as a "really tough sort of problem".
As Chinese President Xi Jinping prepared to inaugurate the Belt and Road Forum, Pyongyang fired a ballistic missile from a base in the country's northwest, near the border with China.
Multiple sets of United Nations and USA sanctions against North Korea have done little to deter it from pursuing its nuclear and missile ambitions.
He says officials are studying possible implications of the launch that came days after South Korea's new president took office and an worldwide conference is being hosted by China.
The U.N. envoy told ABC's "This Week", that the missile test appeared to be meant to send a message to South Korea and said North Korea's missile program was "getting kind of close to home" for Russian Federation.
Japan's Chief Cabinet Secretary Yoshihide Suga says the missile test-fired by North Korea flew 800 kilometers (500 miles) for about 30 minutes and landed in the Sea of Japan, but not inside Japan's exclusive economic zone.
Christopher 'Big Black' Boykin, of MTV's 'Rob & Big,' dead at 45
I didn't want to be known as Rob from 'Rob & Big , ' and I think he didn't want to be known as the sidekick. Navy, hit the limelight with his role as the bodyguard to professional skateboarder and TV host Rob Dyrdek .
It impacted "so close to Russian soil ... the president can not imagine that Russia is pleased", the White House said.
Unsettled by North Korean missile and military nuclear programs, the United States has adopted a war-like posture, sending a strike group to the region and conducting joint military drills with North Korea's regional adversaries, Japan and South Korea.
Newly-elected South Korean President Moon Jae-in also condemned the launch as a "reckless provocation".
Pyongyang defends its missile and nuclear programs as means of protecting the country from USA hostility.
Tensions have been soaring high on the Korean Peninsula over the past weeks.
Before the missile test, the US Treasury said it was considering "every tool in our arsenal" to cut off sources of global financing for illegal activities in the North. Past North Korean missiles have flown farther than Sunday's test, landing closer to Japan, but this launch follows a series of high-profile failures. "And, in the short term, North Korea's missile capability is still some distance from Washington's red line - where it presents a real threat to United States territory".
Skype Update Download Available For Windows 10 OS
Microsoft has released a security advisory for a security vulnerability in the Microsoft Malware Protection Engine. Microsoft has patched a severe flaw affecting many Windows machines.
China, North Korea's most important ally and key provider of food and fuel aid, has sought to cool tensions over Pyongyang's nuclear and missile programs, repeatedly calling for dialogue.
"This missile launch represented no danger for the Russian Federation", the ministry said in a statement on Sunday carried by official Russian news agencies. And the White House says the latest "provocation" should serve as a call for all nations to implement far stronger sanctions against the North.
"Basically, Pyongyang wanted to grab as many chips as possible before sitting down at the negotiating table", Cai said. On Saturday, a top North Korean diplomat said Pyongyang was open to dialogue with the Trump administration under the right conditions.
It said President Donald Trump's "maximum pressure and engagement" policy is only aimed at "stifling us" and will compel the North to "strengthen our nuclear deterrent at the maximum speed".
North Korean attempted but failed to test-launch ballistic missiles four times in the past two months.
North Korea has conducted seven previous launches since the beginning of the year, though the most recent - on April 29 - was a failure, according to South Korean and US officials. It also conducted its fourth and fifth nuclear tests a year ago.
North Korea accuses United States of assassination plot against Kim Jong Un
The half-brother of Kim Jong-un was poisoned with the VX nerve agent at Kuala Lumpur airport and died en route to a hospital. On Monday, President Donald Trump admitted that he'd be "honored" to meet with the North Korean dictator.