The planning, described Sunday by a knowledgeable official, includes ways to provide weapons and other support to the Ukrainian military to resist invading Russian forces — and similar logistical support to insurgent groups if Russia topples the Ukrainian government and a guerrilla war begins.

The weapons the United States might provide include shoulder-fired antiaircraft missiles. The CIA’s delivery of such weapons, known at the time as “Stingers,” had a devastating effect on Soviet forces during their 10-year war in Afghanistan, from 1979 to 1989.

The administration task force, which includes the CIA and other key agencies, has been studying how insurgencies were organized against the Soviets in Afghanistan and Russian-backed forces in Syria — and also against the United States in Iraq and Afghanistan. It’s an ironic example of turning the tables, weighing whether and how to inflict harm similar to what U.S. forces have suffered in recent years.

The task force includes a legal team that is studying how any assistance to a Ukrainian insurgency could be provided without violating U.S. or international laws.