The Terminal High Altitude Area Defense (THAAD) missile system has reached initial operational capacity in South Korea, the US military said on Monday. But officials said it would not be fully operational for some months.
Pyongyang on Tuesday said US actions in the region are pushing the Korean peninsula to the brink of nuclear war.
DPRK ally and neighbour, China, has slammed the THAAD deployment and cautioned that Washington's actions are destabilising the regional security balance.
US President Donald Trump spent the weekend rallying Thailand, Singapore, and even the Philippines in a bid to build support in Southeast Asia to back his position on the DPRK. Trump has said a "major, major conflict" with North Korea is possible, although he said he would be honoured to meet its leader, Kim Jong-un, whom he thinks is a "pretty smart cookie."
TRT World's Nafisa Latic has more.
DPRK, China slam US actions in region
North Korea accused the United States on Tuesday of pushing the Korean peninsula to the brink of nuclear war after a pair of strategic US bombers flew training drills with the South Korean and Japanese air forces in a show of strength.
The two supersonic B-1B Lancer bombers were deployed amid rising tensions over North Korea's pursuit of its nuclear and missile programmes in defiance of United Nations sanctions and pressure from the US and its regional allies.
The US air force said the bombers had flown from Guam to conduct training exercises with the South Korean and Japanese air forces.
North Korea said the bombers conducted "a nuclear bomb dropping drill against major objects" in its territory at a time when Trump and "other US warmongers are crying out for making a preemptive nuclear strike" on the North.
"The reckless military provocation is pushing the situation on the Korean peninsula closer to the brink of nuclear war," the North's official KCNA news agency said on Tuesday.
Pyonyang's sole major ally, China, on Tuesday called for the immediate suspension of the deployment of THAAD.
"China's position is clear-cut and firm. We oppose the deployment of the THAAD system in (South Korea) and urge relevant sides to immediately stop the deployment. We will firmly take necessary measures to uphold our interests," foreign ministry spokesman Geng Shuang said at a regular press briefing.
China said last week the situation on the Korean peninsula could escalate or slip out of control.
Tensions on the Korean peninsula have been high for weeks, driven by concerns that the North might conduct its sixth nuclear test in defiance of pressure from the United States and China.
The North is technically still at war with the South after their 1950-53 conflict ended in a truce, not a treaty, and regularly threatens to destroy the United States, Japan and South Korea.