ABC News' Luis Martinez reports: The deteriorating security situation in Bahrain has led the Pentagon to authorize the voluntary departure of military dependents and non-DOD civilians based at the U.S. Naval base in Bahrain. The base is the home of the Navy’s Fifth Fleet, which conducts operations in the Middle East. Bahrain’s king imposed martial law today after deadly clashes between government forces and Shiite protesters seeking reforms from the Sunni monarchy. Two protesters were killed in today’s violence and there are reports of as many as 200 needing medical treatment. The departure of military dependents is voluntary, which means they will decide whether they want to leave Bahrain or not. If a military plane is headed back to the United States, it could conceivably be used to bring back the family members, but no specific military aircraft will be sent to Bahrain for their departures. Instead, those wishing to leave Bahrain can get reimbursed for buying airline tickets back to the U.S. 6,100 Americans work at the base in Bahrain, 4,200 of them are military and non-DOD civilians. The authorization would apply to the approximately 700 military dependents living in Bahrain and an undetermined number of non-DOD civilians. A statement from the U.S. Fifth Fleet said the voluntary departure was in line with a similar announcement earlier in the day from the State Department authorizing the voluntary departure of non-essential U.S. Embassy staff and dependents. According to the statement, ”The welfare of our personnel and their families is of the utmost importance. This Authorized Departure is being ordered to allow family members who have concerns about their safety to depart without incurring an undue burden. We remain committed to our long-standing partnership with Bahrain. ” There was a mandatory departure of 900 military dependents in 2004 because of terrorism threats. Military dependents were only allowed to return to live in Bahrain just a few years ago.