The additional THAAD launchers are being deployed just days after Trump and his South Korean counterpart, Moon Jae-in, reached an agreement to lift payload restrictions on South Korean missiles, in response to Pyongyang's latest nuclear test on Sunday.
Asked Sunday whether he was going to attack North Korea, Trump said simply: "We'll see".
President Donald Trump said Wednesday that military action is "not a first choice" in the range of options the United States is considering against North Korea.
The North Korean broadcaster said the nuclear test had an "unprecedentedly large power", and that it "marked a very significant occasion in attaining the final goal of completing the state nuclear force".
Federal investigators have been poring over data supplied by ZTE to find links to companies that North Korea has used to tap the USA banking system, the people said. Trump previously promised to visit "fire and fury" upon North Korea in the past if it continues to act provocatively or if it strikes any of America's allies.
Trump said that he believed he and Xi are on the same page following what he described as a "very, very frank and very strong phone call".
Russian Federation and China, which have veto power in the Security Council, may only agree to a partial or temporary oil exports ban, analysts said.
Chinese analysts said it was unlikely that Beijing would support a full oil embargo but a partial cut in supplies could be one option to keep its neighbour in check without bringing down the Kim Jong-un regime.
On the other hand, Chung Kap-su, another second-generation Korean in the town, said he hopes North Korea stops further provocations and pursues a peaceful path by seeking dialogue with South Korea.
The blast, which came weeks after the country fired off two intercontinental ballistic missiles (ICBMs) that appeared to bring much of the mainland USA into range, prompted global condemnation and calls to ramp up sanctions against the isolated nation.
United Nations diplomatic sources said they doubted either China or Moscow, both of which have the power to veto United Nations council resolutions, would accept anything more stringent than a ban on imports of North Korean textiles. The Defense Department said Mattis told Song the USA remains "ironclad" in its commitment to defend South Korea and promised a "massive, effective, and overwhelming military response" if South Korea and other US allies are threatened. A regime collapse is likely to result in a massive influx of refugees.
That sanctions package was expected to put a huge dent in North Korea's economy, cutting its annual earnings by a third.
"But China could take relatively mild measures on oil".
The proposed resolution would add 42 items to a list of equipment, goods and technology that countries are banned from exporting to North Korea. It also banned signatories from hiring and paying more North Korean labourers.
North Korea's latest hydrogen bomb claims points to a significant advancement in the country's burgeoning nuclear programme, which the United Nations had attempted to thwart by imposing several sanctions against the country.