The United States is continuing to arm the Afghan resistance because the Soviet Union has persisted in supplying weapons to the Afghan government, an administration spokeswoman said Monday.

The statement suggests that the administration believes the Soviet Union may be violating an April 14 agreement providing for an end to outside interference in Afghan internal affairs.State Department spokeswoman Phyllis Oakley did not explicitly accuse the Soviets of violating this accord, agreed to in Geneva by Afghanistan, Pakistan and the two superpowers.

However, Oakley said: "At the time of settlement, we indicated to the Soviets that we would continue aid to the resistance unless the Soviets stopped assistance to the illegitimate regime in Kabul. It has not; we will not."

She added a conciliatory note, saying: "If the Soviets exhibited restraint, we would be willing to do so also."

A State Department official who asked not to be identified said the administration interpreted the Geneva accord to bar both superpowers from interfering in Afghani affairs. He said the Soviets have construed it to be a restriction on the United States alone.

"The Soviets knew we interpreted the language to be reciprocal when they signed the agreement," the official said.

Soviet officials have complained of U.S. and Pakistani violations of the accord and have threatened to retaliate by slowing withdrawal of their 115,000 troops from Afghanistan. By the end of June, about 23,000 had left, according to Soviet officials.

The official Soviet news agency Tass last week accused Pakistan of organizing caravans of up to 500 pack animals to carry weapons and ammunition to the area of Jalalabad between June 15 and July 7.