ANALYSIS: How the US government shut down the US Embassy in Ukraine

Russian President Vladimir Putin has been threatening aggressive action against Ukraine for weeks in an attempt to ensure Russian security.

These overtones have increased by the day, forcing the United States and the rest of the world to react and respond to a growing threat to Ukrainian sovereignty, its residents and the tens of thousands of American personnel and citizens living and working in the country.

The need to protect American assets and personnel in country has become more necessary, resulting in a Feb. 12 “Do Not Travel” notification, the highest the State Department issues.

An order was also issued, mandating the immediate evacuation of almost all government personnel in the country and the closure of the U.S. Embassy in Kyiv.

Under any departure circumstance, the Chief of Mission (ambassador) coordinates with the Diplomatic Security Service (DSS) Regional Security officer and the Embassy’s Emergency Action Committee (EAC), which is responsible for planning for and directing emergency responses in times of crisis or during threats against an embassy and/or its personnel.

DSS special agents are the most widely deployed American assets throughout the world, protecting over 275 U.S. diplomatic missions in over 170 countries and 30 U.S. cities. These missions include investigation and protection and enable the agents to get involved in all aspects of American foreign policy, from international criminal identification and apprehension of criminals and terrorists to the protection of important U.S. figures and citizens, such as the secretary of state, the U.S. ambassador to the United Nations and other senior diplomats.

Similar to the recent drawdown of the U.S. Embassy in Kabul, the situation in the Ukraine is forcing the DSS Agents to adapt and respond.

In Kabul, the drawdown triggered the immediate evacuation of all staff from the embassy. In Ukraine, the State Department initially ordered an authorized departure, allowing voluntary relocation of families and some staff, and then moved to an ordered departure, the highest level of non-emergency departure for State Department personnel.

Like a drawdown, an ordered departure is not voluntary. This departure mandates that all family members and non-essential staff are ordered to depart on evacuation status.

Typically, the ambassador will designate the DSS RSO as the incident commander for contingency operations impacting the embassy and its personnel, including during drawdowns or departures.

As the Incident Commander, an RSO is empowered and authorized to do all that is necessary to protect people, property, materials and assets located at the embassy or in country. The first step is to secure and destroy all sensitive information and equipment at the embassy, including those used by the intelligence agencies. This includes facilitating the removal of sensitive intelligence or gear deemed of national security significance back to the United States with the use of DSS Diplomatic Couriers.

To assist, the RSO is empowered and authorized by law to supervise and direct any and all Department of Defense (DOD) assets to include the Marine Security Guard Detachment. In most cases, when a drawdown or departure is authorized, RSOs will call in a supplemental Marine Security Augmentation Unit (MSAU) which can be a force multiplier during the closure of an embassy.

RSOs can also call in additional DSS assets, including elite Mobile Security Deployments (MSD) teams, which is the State Department’s dedicated on-call crisis response tactical element. MSD teams are available to deploy anywhere in the world within 12 hours notice and provide RSOs with supplemental equipment, skills and capability similar to a military Special Operations team.

Unlike their DOD counterparts, these MSD teams are exclusively made up of specially selected and trained DSS special agents, not soldiers.

While securing the embassy and destroying sensitive information and equipment is critical, the evacuation of Kyiv embassy personnel is also a priority.

Depending on the circumstances on the ground, the evacuation of personnel can be facilitated by commercial or DOD assets. In the case of Kabul, DOD assets were used but the sensitivity of the situation in the Ukraine means the RSOs had to coordinate and rely on commercial modes of travel outside of the capital to Lviv or other parts of Eastern Europe.

And while the RSOs are handling the evacuation of embassy personnel and the closure of the embassy, the fate of American citizens, an estimated 30,000 in Ukraine, must also be factored into the planning and execution. Under the State Departments’ “No Double Standard” policy, American citizens were warned to leave the country due to the threat. They can leave by commercial means or, if an emergency happens, work with the U.S. Embassy to get out.

As the embassy in Kyiv was secured, the last Americans to leave were the DSS agents assigned there. One of their final tasks was to lower the United States flag and ensure the ambassador safely takes it and then secure compound.

But even with the embassy closed and flag removed, the State Department has announced this is hopefully a temporary measure, meaning that when the circumstances are right, the embassy building could be reopened.

When that happens, the DSS personnel will be the first back in.

Donald J. Mihalek is an ABC News contributor, retired senior Secret Service agent and regional field training instructor who served during two presidential transitions. He was also a police officer and in the U.S. Coast Guard.