It was late in the afternoon when the phone rang in the parish office of the Immaculate Conception Church.
The call came from Nicaragua's governing junta -- and its message was one that has quickly put the Roman Catholic Church here and the Nicaraguan government on a collision course.
The message was a virtual order that the church postpone its annual Good Friday mass from its traditional early morning hour to late in the afternoon.
Holding the annual mass at 9 a.m., the government said, would conflict with its earlier decision to suspend the traditional semana santa vacation in the week before Easter -- a national vacation to which Nicaraguans are accustomed.
The government argues that Nicaragua is facing ''a real and imminent threat of invasion'' from the United States. And in this period of crisis, it says, vacations must be forfeited and all Nicaraguans, including the church, must adjust.
Without debating the legitimacy of the government's view, the church, to which the majority of Nicaraguans are nominally attached, has decided to defy the government order.
It is going ahead with plans to hold the mass on Friday morning. It also plans to stage a church procession Saturday, despite the rumored desire of Nicaragua's leftist-leaning Sandinista leadership to cancel the event. Last year's Saturday procession attracted 100,000 persons.
Roman Catholic Archbishop Miguel Obando y Bravo, primate of Nicaragua, considers the demand to reschedule the mass as an affront to the church.
Church authorities also are calling the government's handling of its order ''insulting.'' The government had not consulted the church before delivering its message, the archbishop said in an interview with this reporter. And the government did not communicate its wishes to the archbishop directly; instead it notified just one of the 20 Roman Catholic churches here.
The person who received the government's message at the Immaculate Conception Church works for the Rev. Bismarck Carballo, spokesman for the Managuan diocese. In the archbishop's view, the message was an issue for his office, not one for the church spokesman.
The Nicaraguan government has long been feuding with Archbishop Obando y Bravo. The archbishop -- a short, stocky man with graying hair -- turned aside the personal affront, but clearly stated his answer to what he called the government's ''order.'' The church will not comply.
''We are going to try to hold the mass (as usual),'' he said. ''I do not know what will happen. We hope everything will be peaceful and that the authorities will not take a severe attitude.
''We already have our program,'' he said, ''and we are going ahead with it.''
When asked about the possibility of confrontation with the Sandinista government, Archbishop Obando y Bravo smiles. He is no stranger to confrontation. He struggled for 10 years against the late Gen. Anastasio Somoza Debayle, overthrown by the Sandinistas in 1979.
The archbishop now seems to be prepared to struggle against the Sandinistas.
Relations between the church and government have been cool in the nearly three years since the Sandinista victory.
In February, church-state relations took a turn for the worse when the Nicaraguan episcopal conference, composed of Archbishop Obando y Bravo and the country's other Roman Catholic bishops, protested the nation's resettlement of Miskito Indians in northeastern Nicaragua.
In a statement, they cited government ''relocations of individuals . . . without warning and without conscientious dialogue''; forced marches ''without sufficient consideration for the weak, aged, women, and children''; ''the destruction of (Indian) homes, belongings, and domestic animals'';and the deaths of some Indians.
''Such are the facts that compel us to denounce vigorously such attitudes of those who have the power and force,'' ''because they must be the first to guarantee observance of these human rights,'' the bishops said.The government, they said, had created ''a situation of disrespect to the dignity of the human person and the violation of their rights.''Government officials have directly and indirectly attacked the bishops' statement.
Leaders of Nicaragua's so-called ''popular churches'' - served by dissident Roman Catholic priests - supported the government following the bishops' charges.
Pro-government newspapers and radio also back the Sandinistas on the Miskito issue, sometimes specifically criticizing the Roman Catholic Church.
Roman Catholic officials here say the number of priests who helped form the ''popular churches'' are few. But in church circles there is concern that the influence of these churches is growing, that the popular churches have plenty of money, and that they are Marxist-Leninist in ideology.''Popular'' priests admit that their churches are a mix of religion and politics. But they defend this on the ground that the two must mix because both deal with the lives of human beings.
Just this past week, Tomas Borge Martinez, one of the Sandinista directorate, addressed the congregation of one such church. His address linked priests, Christians, and revolutionaries.
Roman Catholic officials view such remarks as a mockery of religion. They say it is false theology.
There is also a growing clash between Roman Catholic officialdom and the half dozen Roman Catholic priests serving in the government. The bishops have tried to force these priests to resign from government but so far without success.
''If it doesn't happen this week,'' says one priest, ''it will happen next week or the week after. For we cannot accept the government's efforts to put more and more limits on . . . freedom of religion.''