WASHINGTON — The White House on Thursday requested $500 million to help train and equip vetted rebel groups in Syria as part of a $1.5 billion Regional Stabilization Initiative to deal with the growing instability from the four-year crisis.

The request is part of a $65.8 billion request for the special war fund known as Overseas Contingency Operations (OCO) that fills in what had until now been a blank placeholder in President Obama's budget request for fiscal year 2015. The Regional Stabilization Initiative, which must still be approved by the House and Senate, is part of a $5 billion counterterrorism partnership fund that the president announced during his commencement address at West Point last month.

"The administration is requesting $1.5 billion to advance US interests in partnership with Syria’s neighbors — Jordan, Lebanon, Turkey, and Iraq — to promote internal stability and to provide support to communities hosting refugees," the White House said in a fact sheet about the OCO program.

Two-thirds of that would be allocated to the departments of State and Defense for "programs to allow the United States to make investments in Syria’s neighbors to enable them to strengthen internal and border security capabilities and enhance their capacity to manage the pressures created by ongoing conflicts and the stresses on communities hosting refugees." These would include "training and equipment required to improve border security and the capacity of police and counterterrorism units to ensure internal stability" as well as the "growing costs in communities hosting refugees to strengthen the delivery of essential services such as education, health, food, sanitation and water."