The planned deployment of the THAAD missile defense system to South Korea was a key topic of talks between US President Barack Obama and South Korean President Park Geun-hye, a senior White House official said.

Park and Obama held a one-on-one meeting on the sidelines of a regional summit in Laos, reaffirming their determination to counter North Korea's continued provocations and agreeing on the importance of China's role in enforcing sanctions on Pyongyang.

White House Deputy National Security Advisor Ben Rhodes said that the "shared commitment" between the two countries to deploy the Terminal High Altitude Area Defense missile defense system was also a main point of discussions, given the North's repeated provocations and the development of ballistic missiles.

"One of the things the two leaders focused on was our determination to move forward with the deployment of the THAAD system, which protects US personnel in the Republic of Korea, protects our allies, and it ultimately is necessary to counter the threat from North Korean ballistic missiles," Rhodes said at a briefing in Laos, according to a White House transcript.

After the summit, Obama said the US and the South will work together to make sure to close loopholes in sanctions on the North and making them even more effective. The two sides also agreed that the entire international community needs to implement the sanctions fully and hold North Korea accountable, Obama said.

Rhodes said that Obama and Chinese President Xi Jinping also discussed sanctions enforcement.

"We have over many years seen North Korea try to find ways to evade sanctions, try to find ways to access foreign currency, try to find ways to access sensitive technology using front companies for their activities," Rhodes said.

"We want to make sure that we're just cutting off all the lifelines that North Korea tries to grab onto in terms of evading sanctions and accessing currency so that they pay the full cost for their actions," he said. (Yonhap)