SEOUL • South Korea does not aim to change its agreement with the United States on the deployment of an anti-missile system and will continue to work closely with the US on it, the South's top national security adviser said yesterday.

A decision to postpone the full deployment of the Terminal High Altitude Area Defence (Thaad) system pending a review of its environmental impact was a domestic measure to ensure a democratic process, Mr Chung Eui Yong said.

US ally South Korea said on Wednesday that it would hold off on installing remaining elements of the Thaad system, which China strongly objects to, until the environmental study was completed.

"The decision to introduce Thaad was made to protect South Korea and the US forces in South Korea from a growing threat from the North. We won't take this decision lightly," said Mr Chung.

During his election campaign in May, South Korean President Moon Jae In promised to review the Thaad deployment, a decision made by the government of his predecessor Park Geun Hye.

China said the system's powerful radar can penetrate deep into its territory, undermining its stability and unsettling the regional balance. China also said the system does nothing to deter North Korea.

The US and South Korea said Thaad is aimed only at defending against North Korean missiles.

Two launchers of the full six-launcher Thaad battery, as well as its radar, have been installed at a site on what used to be a golf course near the south-eastern city of Seongju. Those elements will stay in place.

Officially, the delay, which may take well over a year, is to allow for a new, comprehensive environmental impact assessment. However, analysts say the move is a strategic delay by Mr Moon to dodge the tricky diplomatic situation he inherited.

"South Korea is caught between China and the United States... it can't turn its back on either China, its largest trading partner, or the United States, its key ally," said Chonnam National University political science professor Yoon Sung Suk.

"Moon is playing for time, trying to avoid irritating Washington but find a way to wiggle out of the current diplomatic impasse," Prof Yoon said, adding that Mr Moon could be hoping that by the time the probe is finished, the security landscape would have changed.

"It's given him a year, and in the meantime, he'll be doing his utmost to make diplomacy work on the North Korea issue."

Meanwhile, Kookmin University's Professor Andrei Lankov said Beijing's economic retaliation, ordered in April as Thaad was partially deployed, is now likely to be eased to "reward" Seoul for the suspension.

Professor Kim Dong Yub at the Institute for Far Eastern Studies at Kyungnam University said the deployment of Thaad was approved by Park and as it became apparent she would lose power, the administration started "hurrying up with the deployment, sidestepping due procedures and shrouding it in secrecy".

Mr Moon this week removed a Park-appointed Defence Ministry official for "intentionally" doctoring reports to hide the fact that four new launchers had arrived.

Prof Kim said there was no question that the system would be deployed - eventually.

"It is unthinkable that South Korea makes a U-turn, which would upend the decades-long alliance with the US."

REUTERS, AGENCE FRANCE-PRESSE