"China continues to have both economic and political influence" over North Korea, Spicer said. North Korean Dictator Kim Jong un is seen waving to the crowd during the festivities.
The North has said such launches are an act of deterrence against a potential invasion by the US or South Korea.
U.S. Vice President Mike Pence has arrived in Japan for the second stop of a 10-day Asia tour.
The loss of US participation in the TPP was a blow to Japan following strenuous negotiations, especially over opening access wider to its long-protected farm sector.
"While all options are on the table, President (Donald) Trump is determined to work closely with Japan, with South Korea, with all our allies in the region and with China to achieve a peaceable resolution and the de-nuclearisation of the Korean peninsula", Mr Pence said before lunch with Japanese Prime Minister Shinzo Abe.
Chief Cabinet Secretary Yoshihide Suga told reporters over the weekend that Japan might push ahead with a revised, 11-nation version of the TPP despite the US rejection of the trade accord.
Then, less than a week later, the U.S. military dropped a 10,300kg bomb - the largest non-nuclear bomb ever used in combat by the USA - on Isis (Islamic State) forces in eastern Afghanistan.
But Kim Jong Un, North Korea's current leader, only took power in 2011, during the Obama years.More news: New contender in hunt for alien life discovered by astronomers
But any strikes against the North would probably bring the USA into a diplomatic crisis with China, the North's main economic lifeline.
President Trump has signaled that he will not hesitate to take military action against enemies of the United States, as evidenced by his bombing of a Syrian airfield and an ISIS cave in Afghanistan last week.
In response, the general staff of the North Korean armed forces threatened to launch a strike against U.S. military bases in Japan and South Korea, as well as the presidential residence in Seoul in case of USA aggression.
Russia's Foreign Minister Sergey Lavrov warned the USA against taking unilateral military action in North Korea on Monday at a press conference in Moscow.
As tensions continue to rise, the world remains fixated on the nuclear showdown between North Korea and the United States, the subject of the week's Rasmussen Minute.
Hwang and Pence on Monday reaffirmed their plans to go ahead with the THAAD, but the decision will be up to the next Korean president.
Lavrov's comments come after President Trump's authorization of a strike on a Syrian airbase two weeks ago caused a flurry of speculation that North Korea might also face military action in response to further provocations. He has since praised China for trying to increase pressure on Pyongyang. China has imposed a painful economic boycott on South Korean exports and is making life hard for South Korean companies in China.
Before Mr. Trump softens any trade deals with China, Townsend said the administration needs to see "definite signs" that China is working to mount pressure on the North.