The disclosure is an effort to follow through on the Obama administration's 2013 promise to provide more transparency in its drone program.
The United States is currently considering imposing additional economic sanctions on North Korea following the increasingly belligerent nation's rocket launch earlier this month. South Korean defense officials are expected to ask for more material assistance next week.
The US Navy confirmed that a sonic boom that shook New Jersey and other nearby states was likely caused by flight testing off the coast of Maryland.
Twelve Marines have been missing since late Thursday night, when their Super Stallion helicopters failed to return to base. Searchers have found life rafts, but no crew members.