The Carter administration has expelled two Libyan diplomats for distributing among Libyan students in the United States documents calling for the assassination of opponents of Libyan leader Col. Muammar Qaddafi, well-informed sources said yesterday.

State Department officials said the two diplomats were also using coercive methods to control Libyan students in the United States and that their conduct was "inconsistent with the accepted role of diplomats."

Moftah S. Ibrahim, third secretary, and Muhamed S. A. Tarhuni, a cultural attache, were given 48 hours to leave the United States after being declared persona non grata April 5. Both men have left.

Sources said that the "literature of violent nature" distributed by the two diplomats called on Libyans to "march against embassies" and to carry out "physical elimination of the enemies of the revolution abroad."

The call for assassination of political opponents was contained in the program declaration adopted by the Libyan Revoluntionary Committees meeting in Benghazi last February. The Libyan Embassy here was said to have circulated the program among Libyan students in the United States, whose number is estimated between 3,000 to 4,000.

The two diplomats are also said to have been involved in organizing a campaign to prevent expressions of opposition to Qaddafi among the students.

A Libyan journalist living in exile was assassinated in London last week by two gunmen believed by sources here to have been sent by Libya to eliminate Libyan political exiles.

Qaddafi in a speech two weeks ago publicly called for the assassination of opponents of his revolution who are living abroad.

The State Department has kept silent on the two diplomats' esplusion in an effort to forestall Libya's retaliation against the last two remaining American diplomats in the Libyan capital of Tripoli. The two U.S. diplomats had been sent on a "shopping trip" to Tunisia just before the explusion order, but they are now back at their post.

All other American personnel in Libya was withdrawn last December when a Libyan mob attacked the U.S. Embassy in Tripoli and set fire to furniture. No one was hurt in the attack organized as a demonstration of support for Iran's revolution.

Libya supplies 10 percent of U.S. oil imports and is the third most important U.S. source of foreign oil. Libya is among the few nations to have said publicly it would help Iran in the event of a U.S. attack.

Libya is also among the most radical Arab countries and its relations with Washington have been strained since Qaddafi overthrew King Idris in 1969.

It is unclear whether there are any outright opponents of the Qaddafi regime among the Libyan students in this country. Encouraged by Qaddafi, the students are currently in control of the Libyan mission here, which has been renamed a "people's bureau."

U.S. officials dealing with Libyan affairs said that a five-member student committee is in charge of the mission. None of them has diplomatic status and all were elected by other students in the United States.

Washington's diplomatic list includes the names of 20 Libyan diplomats who "continue their normal functions" under the five-member student committee, according to the officials. They said that "informal, unofficial" contacts between the committee and the State Department have taken place.