WASHINGTON — Despite appeals from the Ukrainian armed forces, the United States has so far provided only a modest package of nonlethal assistance to the Kiev government, and much of it has yet to arrive.

The White House, which has relied on economic sanctions and the threat of international isolation to deter Russia from escalating its involvement in Ukraine, has been reluctant to step up military assistance for fear that it will lead to an escalation in the fighting and provoke Moscow.

The $70 million in aid the United States has pledged includes rations, radios, concertina wire, first-aid kits and limited supplies of body armor, but no arms. But much of the assistance is still in the pipeline, including such important items as night-vision goggles. The United States has also promised to train 700 members of Ukraine’s National Guard, but that program is not scheduled to get underway until 2015.

In contrast, Ukrainian separatists have been battling the government’s troops with the help of Russian tanks, artillery, antiaircraft weapons and, NATO says, thousands of Russian troops.