Members of El Salvador's Opposition Democratic Revolutionary Front charged yesterday that the junta rule there has moved to the "extreme right" and they maintained that it would fall without direct U.S. political, military and economic support.

"The people who really rule are the military," said Enrique Alvarez, president of the coalition of political, union, guerrilla and mass-movement organizations. "They have no support of the people, but only of the United States, Venezuela and Guatemala. The only way they stay in power is through repression."

The five front members are visiting the United States as part of a global tour to seek international support for their efforts to oust the U.S.-backed civilian-military coalition government that took over in El Salvador in a coup last October. Some of the front members once supported the junta, but quit to form the opposition group in April.

The Junta, with U.S. prodding, has instituted a series of land and financial reforms to change the economic structure of the country. But the front has charged, with the concurrence of international human rights groups, that the Salvadoran military uses the land reform as an excuse to massacre peasants in its efforts to stamp out organizational efforts of the left. Salvadoran church officials estimate that more than 2,000 people have been killed in political warfare since the beginning of the year.

Although the United States, in tacit recognition of the front's popular backing within El Salvador, has repeatedly asked its more moderate member groups to participate in the junta government, front members said they no longer have any confidence in that government.

At the same time, U.S. officials say they cannot deal directly with the front itself, because of its incorporation of guerrilla groups who advocate violent overthrow of the junta. The State Department also says civilian members of the front have no real control over its military activities and would play no real part should the guerrillas take over in a civil war.

Ruben Zamora, a former Christian Democrat and junta minister before his resignation last January, said that party had "tried for many years, in different ways, to change" the structure of economic and political repression "through elections," which he said were "marked by fraud."

Later, "an alliance with the military . . . failed because the civilian part of the government had no control over the military, and they were killing the same people we were trying to dialogue with," he said. "The only way left now is armed struggle." The demanded total U.S. withdrawal, from El Salvador.

The five front members will remain in Washington this week for meetings with congressmen and diplomats.No meetings with the State Department are planned.