The Reagan administration has decided to ask Congress for funds to resume military assistance to Guatemala but does not propose to spend the money unless political conditions in that country improve, State Department sources said yesterday.

As a first step, officials said, $250,000 has been included in the administration's fiscal 1983 budget to finance U.S. military training for Guatemalans.

This budget request, however, is being described as a way of obtaining spending authority in case a decision is made later to go forward with the training program. The decision to spend "has not been made," a State Department official said.

The administration's budget presentation, according to officials, also will address "the possibility" of cash sales of military equipment such as spare parts. But no decision has yet been made to authorize such sales, the officials added.

Guatemala has received no U.S. military assistance since the Carter administration terminated it in 1977 due to human rights abuses. The Reagan administration has signaled for months that it would like to resume military sales and aid, but has been constrained by strong opposition in Congress generated by reports of government death squads and other abuses.

The State Department human rights report sent to Capitol Hill last week said that politically motivated killings in Guatemala have risen from 70 to 100 per month in 1980, to 250 to 300 per month in 1981, with no evidence of arrests or prosecutions.

While Guatemala is afflicted with violence from both the right and the left, according to the report, "the greater number of apparently politically motivated killings are probably attributable to groups associated with the extreme right or with elements of government forces, rather than to the extreme left."

Without being specific, State Department spokesman Dean Fischer told reporters yesterday that "we want to assist Guatemala in the face of growing insurgency while being mindful of the important element human rights plays in our foreign policy formulation." He said the question of military sales to Guatemala "continues to be under review."

"A savage war is going on between the Guatemalan military and externally supported insurgents," Fischer said. He added that elections are scheduled in that country March 7, suggesting a U.S. hope that the vote will improve the political picture in ways that will justify a resumption of U.S. aid.