A former senior official of the U.S. Defense Department says she believes South Korea's intent to extend the range of its ballistic missiles is not the best option to counter North Korea's missile threat.

Michele Flournoy, who served as undersecretary of defense for policy in the Obama administration, made the remark during a seminar organized by the American Enterprise Institute in Washington on Tuesday.

Flournoy stressed that North Korea's missile threats should be approached “as a problem for the alliance.”

She said South Korea has much to do for the transfer of wartime operational command, including modernizing its military. She explained that South Korea should first consider whether it can address the North Korean threat differently through its alliance with the U.S. before putting resources toward extending the range of its ballistic missiles.