Trump has been pressuring China, North Korea's main benefactor, to help defuse the situation over North Korea's development of atomic weapons and long-range missiles but he has also warned that the USA will settle the issue alone if other countries won't help.
North Korean soldiers with weapons attend military training in an undisclosed location.
A North Korean missile blew up nearly immediately on its test launch on Sunday, the USA military said.
"It is a situation where a lot of (military) exercise equipment is amassed in North Korea and also a lot of strategic assets are situated on the Korean peninsula because of the South Korea-US military drills", Lee told a briefing.
US House of Representatives Speaker Paul Ryan, on a visit to London, said the military option must be part of the pressure brought to bear.
Shen reminded his audience that when China and South Korea normalized relations in 1992, the China-North Korea treaty alliance between the two countries became nothing but "scrap paper".
But he and other USA officials have yet to outline a strategy that differs markedly from that of previous administrations.
North Korean leader Kim Jong Un claimed to be having an upper-hand in the country's stained relationship with US when a video simulation of a North Korean nuclear missile attack was featured destroying what appears to be an unidentified American city. "Through this exercise, I am sure we can deter war and remove our enemy's intention to provoke us".
North Korea last Saturday tried and failed to launch a missile from its submarine base at Sinpo off its eastern coast, the latest in a series of missile tests that violate United Nations sanctions against the North.
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"Worn-out United States accusations can't mask its admission of Iran's compliance with JCPOA". North Korean state media warns of a "super-mighty pre-emptive strike" after U.S.
South Korean presidential front-runner Moon Jae-in is pulling ahead in the polls as a May 9 election looms. It has been claiming that Kim's regime has already developed an intercontinental ballistic missile capable of delivering a nuclear warhead to the mainland US.
The North conducted two nuclear bomb tests and 24 ballistic missile tests last year, defying six Security Council sanctions resolutions banning any testing, and it has conducted additional missile tests this year, including one on Saturday that failed.
"Beijing has demonstrated due enthusiasm for Washington's newfound interest in a diplomatic solution and willingness to work more closely with it", the state-run China Daily said in an editorial.
Previous statements denouncing earlier missile launches "welcomed efforts by council members, as well as other states, to facilitate a peaceful and comprehensive solution through dialog". The latest draft statement dropped "through dialog" and Russian Federation requested it be included again. Such statements are agreed by consensus.
Chinese Foreign Ministry spokesman Lu Kang referred questions about the air force to the Defence Ministry, which has yet to publicly comment.
In Moscow, Russian Foreign Minister Sergey Lavrov told reporters he hopes "there will be no unilateral actions like those we saw recently in Syria and that the USA will follow the line that President Trump repeatedly voiced during the election campaign".
DONALD Trump has said how much North Korea's leader desires peace will be a deciding factor in easing tensions between his nation and the United States.
The U.S. military's Pacific Command explained that the USS Carl Vinson strike group first had to complete a shorter-than-planned period of training with Australia.
The footage also showed the missiles, flying right across the Pacific Ocean heading towards the western United States coastline, before it appealingly destroyed San Francisco.
Behind the heated rhetoric, Trump's strategy in the region looks somewhat similar to predecessor Barack Obama's - albeit with the added unpredictability of a new president who has shown he's willing to use force.