The United States will consider "all options" to beef up the defense of South Korea after the North's nuclear test, the Pentagon spokesman said Thursday, suggesting the possibility of deploying additional U.S. strategic defense assets to the Asian ally.

"We're in ongoing conversations ... with the South Koreans and with our other allies in the region, about additional steps that may or may not need to be taken in order to respond to the latest actions from the North Koreans," Pentagon press secretary Peter Cook said at a briefing.

"We're confident that we, again working in lockstep with the South Koreans, can respond appropriately to this action. We'll continue to view with them all options that need to be considered at this point," he said in response to a question whether Seoul or Tokyo asked for additional military equipment to help counter North Korean threats.

White House press secretary Josh Earnest said that any U.S.

military capabilities deployed to South Korea are arrayed "solely against the threat that is posed by the North Koreans."

"It certainly is a testament to our commitment to the national security of our allies in South Korea," he said.

Earnest said, however, that there have been no discussions or consultations with the South Koreans about the deployment of a THAAD missile defense battery. (Yonhap)