The Soviet Union has asked the United States to return a Russian soldier who took refuge Monday in the U.S. Embassy in Kabul, Afghanistan, according to State Department officials, who made plain that the United States is not inclined to do so.

Instead, officials said yesterday, the United States has turned to the U.N. High Commission for Refugees for help in establishing the soldier's status as a legitimate refugee seeking asylum.

The U.N. agency is reported to have agreed to interview the trooper, whose name was withheld but who was described by officials here as "a simple soldier . . . a plain enlisted man." However, the U.N. unit would have to send a representative from outside Afghanistan, and thus obtain Afghan approval to do so, in order to perform the interview.

The United States is also asking Afghan authorities for permission to send a Russian-speaking diplomat to Kabul to talk to the defector. With a touch of embarrassment, State Department officials reported that no "fluent" Russian speaker is among the 18 U.S. personnel, including six Marine guards, who remain in the embassy in Kabul.

According to a State Department account, the Soviet soldier marched past Afghan security guards at the embassy gate early Monday.The soldier, who was armed, caused a commotion among embassy officials until it was determined through "pidgin Russian" and sign language that he sought refuge in the embassy and asylum in the United States.

Under ordinary circumstances Russian-speaking U.S. officials could speak to the soldier by telephone from Washington or elsewhere. However, telephone communications to the U.S. Embassy in Kabul were severed several weeks ago by the Afghan switchboard, according to State Department officials.

Shortly after the Soviet soldier was seen entering the U.S. Embassy, Afghan security around the compound was increased, the State Department reported.This appeared to be intended to prevent a repetition of the defection, which is believed to be the first by a member of the 85,000-strong military force in Afghanistan.

Soviet Ambassador to the United States Anatoliy F. Dobrynin was summoned to the State Department Monday to be informed about the soldier by Undersecretary of State David D. Newsom.

According to State Department spokesman John Trattner, the United States emphasized Soviet responsibility for the safety and security of American diplomatic personnel in Kabul. This appeared to be a preemptive warning against the possiblity of retaliation or physical pressure against Americans there in connection with the defection.

It is not yet clear, according to officials here, what the definitive position of the Soviet and Afghan authorites will be about the defector. Both those governments have been informed that the United States is handling the case in keeping with its standard policies on providing refuge to those who seek it at a U.S. diplomatic post.

If the Soviet soldier maintains his present stand and the Soviets and Afghans take a hard line against his safe transfer to the United States or some other country acceptable to him, the United States could face a long standoff, during which the defector would remain an embassy resident.

The defecting soldier adds a new complication to strained U.S.-Soviet relations as Secretary of State Edmund S. Muskie prepares to meet Soviet Foreign Minister Andrei A. Gromyko at the United Nations Sept. 25.

The main achievement of the Muskie-Gromyko meeting, according to U.S. officials, is likely to be agreement on a first round of preliminary talks about the limitation of medium-range missiles in Europe. The Soviets have indicated atheir likely aagreement to begin such talks in mid-October at the level of senior experts, officials said.