North Korean leader Kim Jong Un oversees special forces operation

"Very powerful", Trump said on Wednesday.

America sent a US Navy strike group towards the Western Pacific in a show of force, while North Korea warned it would launch a nuke attack in response to any act of aggression.

China is willing to work with the US on ending North Korea's nuclear-weapons program but wants a peaceful solution to the escalating conflict, Chinese President Xi Jinping told President Donald Trump in a phone call Wednesday.

Tensions in the Korean Peninsula are increasingly on edge this week as North Korea prepares to celebrate the birthday of Kim Il-sung, its founding father, on Saturday.

"Right now you have two leaders, President Trump and Kim Jong-un, who both feel emboldened", he said. State media later confirmed the launch had failed. It tested a newly developed intermediate-range missile on the anniversary a year ago, a launch that also failed.

A U.S. monitoring group, 38North, has described the Punggye-ri test site as "primed and ready".

Reuters reports that recently a fleet of North Korean cargo ships were loaded up with coal at Chinese ports before heading back home to the port of Nampo.

Tensions remain high amid concerns the North could conduct its sixth nuclear test or launch more missiles in defiance of United Nations sanctions.

"China consistently decides its positions and policies on important global issues based on their own merits", Foreign Ministry spokesman Lu Kang told reporters on Thursday.

Asked if there was hope that China would do more to slow or suspend its nuclear programme, he replied: "I'm counting on it".

The intelligence officials told NBC News that the USA has positioned two destroyers capable of shooting Tomahawk cruise missiles in the region, one just 300 miles from the North Korean nuclear test site. While Trump has repeatedly said that all options are on the table, which could include military action, he has indicated he will for now let China try to restrain the North while leaving room open for Washington, if this strategy fails, to take military action or even conduct a pre-emptive attack on the North.

Wu Dawei, China's special envoy for Korean peninsula affairs, will visit North Korea on Friday, the Maeil Business Newspaper reported, citing an unidentified South Korean politician.

China's insistence on a peaceful approach is rooted in its belief that any attempt to denuclearize the North by force would bring cataclysmic results upon all sides, including China, Ruan said.

"It also points to extreme adventurism on the part of the current U.S. administration", he said.

President Donald Trump waxed lyrical about his good "chemistry" and "bonding" with Chinese leader Xi Jinping Wednesday - a rhetorical U-turn which the White House believes is already paying dividends.

And China moved 150,000 soldiers close to the North Korea border in preparation for war.

Nearly all coal shipments to the Chinese city of Dandong, on the North Korean border, since February have been turned back, a source with knowledge of North Korean government operations in Dandong told CNN.

Prime Minister Shinzo Abe of Japan also warned that North Korea may be capable of firing a missile loaded with sarin nerve gas toward Japan.

But a senior Japanese diplomat said Japan also did not see a high risk of military action.

"It fears a united Korea under South Korean leadership, which could lead to U.S. troops on China's border".

Photographer Eric Lafforgue captured the images while in North Korea.

North Korea depends on China for 90 percent of its crude oil supply, and stopping these will wreak havoc on the dictatorship, which China has been trying to avoid, since a regime collapse is likely to result in a massive influx of refugees.

Coal accounted for a third of all official North Korean exports in 2015, making up a large part of their income.