Sandinistas, Contras Swap Charges on Ambush : Nicaragua: A survivor of Monday’s attack says it was too dark to see who attacked the group of church workers.

U.S.-backed Contras and the leftist Sandinista government on Wednesday traded accusations over an attack that killed two nuns, one an American, and wounded two other church workers in a remote area of Nicaragua.

President Daniel Ortega lashed out at the United States, declaring: “The North American government is responsible for this crime because it pays the Contras to commit these crimes.”

And Barricada, the official Sandinista newspaper, called the attack, which took place Monday, “a premeditated ambush” by the Contras.

But a Contra leader said Wednesday that his group was “incapable” of the attack, saying that Nicaragua blamed it on the rebels to rob them of U.S. congressional support.

“We protect the civilian population, we are Catholic, and we support the episcopal work of the Catholic Church,” Aristides Sanchez, of the Nicaraguan Resistance, said on Costa Rican Radio.

In Washington, White House spokesman Marlin Fitzwater told reporters, “We deplore in the strongest terms this outrageous attack on religious workers and extend our deepest sympathy to the families of the victims.”

But he added: “The Nicaraguan government has provided no information to substantiate its charge that the Contras launched the attack, and we hope the Sandinistas do not seek to obscure this tragedy by engaging in a propaganda battle.”

The body of Sister Maureen Courtney will be flown to her hometown of Milwaukee today after a memorial service Wednesday in a Managua church.

Sister Courtney, 45, and Sister Teresa Rosales, 24, of Nicaragua, were killed when their pickup truck was attacked in a Caribbean coastal region near the town of Puerto Cabezas in northeastern Nicaragua.

The area is in Zelaya province, 250 miles northeast of Managua, the capital.

Both nuns belonged to the Order of St. Agnes, as did Sister Francesca Maria Colomer, 24, a third nun who suffered face and body wounds. Auxiliary Bishop Paul Schmitz, 46, from Fond du Lac, Wis., and of the Capuchin order, was wounded in the left arm.

The two were being treated Wednesday in a Managua military hospital and are expected to recover.

Sister Courtney had been doing missionary work in Nicaragua for 15 years. She was believed to be the first American killed in the nine-year-old civil war since Contras killed 27-year-old engineer Benjamin Linder of Portland, Ore., in April, 1987.

Sister Jean Steffes, mother superior for the Sisters of St. Agnes, said in Fond du Lac on Wednesday:

“Both sisters were killed instantly as result of gunfire. The white pickup truck in which the group was traveling was clearly marked with yellow crosses.

“When those still alive in the truck shouted they were religious, the firing ceased, but by then two were dead.”

Nicaragua’s Roman Catholic Church said it does not know who attacked the church workers.

Before flying to Managua on an air force plane, Schmitz told reporters in Puerto Cabezas he did not know who attacked them, saying it was dark at the time.

“I only know that a mine went off, or a grenade, and there was heavy shooting afterward,” Schmitz said. “We identified ourselves, but nobody came to the pickup.”

Sanchez denied that the Contras were involved and accused the government of staging the attack.

He said the Nicaraguan Resistance, an umbrella group of anti-Sandinista organizations in exile, regrets the incident but stressed that the rebels “are incapable of taking such an action.”

In comments over the Costa Rican station Radio Impacto, monitored in Managua, he called the Sandinista charges “a propaganda campaign” to deprive the rebels of U.S. congressional support.

“That sort of campaign is to be expected on the part of the Sandinistas when a change in the aid by the U.S. Congress is getting near,” Sanchez said.

Congress must soon decide whether to continue the non-lethal aid it has been giving the Contras since February, 1988. The aid package for the rebels runs out after Nicaragua’s general elections, scheduled for Feb. 25.