Two American journalists were killed yesterday when their car came under fire during cross-border fighting along the Honduran-Nicaraguan frontier, according to reports from the Honduran capital.

According to the U.S. Embassy and Honduran military sources reached by telephone in Tegucigalpa, the two were identified as Los Angeles Times correspondent Dial Torgerson, 55, and Richard Cross, 31, a free-lance photographer on assignment for U.S. News and World Report. A Honduran driver with the two, identified as Juan Jose Herrera, 27, was reported in critical condition.

The car reportedly was hit by a projectile, probably a rocket-propelled grenade, at about 3 p.m. local time (5 p.m. EDT) on a dirt road between the towns of Cifuentes and Los Trojes. U.S. and Honduran officials said that heavy rifle fire from Nicaragua prevented the recovery and positive identification of the bodies by the Honduran Army until 10:30 p.m. (12:30 a.m. EDT).

Earlier reports that Time Magazine correspondent William McWhirter had been traveling with them later were proved false when McWhirter was located in Miami. The initial reports from the Honduran Foreign Ministry had said that four persons had been in the car, and that they had been identified by a truck driver traveling behind them only as having "light complexions."

The Honduran Foreign Ministry issued a formal protest to the Nicaraguan charge d'affaires in Tegucigalpa last night charging that the car had been fired upon "by the Sandinista army" from the Nicaraguan settlement of El Porvenir. "The journalists were traveling in a tourist car on the highway from Los Trojes to Cifuentes and in the above-mentioned place were attacked by grenades fired from Nicaraguan territory."

There was no immediate Nicaraguan response, and government sources in Managua said that they were still trying to sort out what had happened in the remote outpost.

The Honduran towns of Cifuentes and Los Trojes lie on either side of a triangle-shaped piece of Nicaraguan territory jutting into Honduras. Los Trojes is virtually on the border across from the Nicaraguan settlement of El Porvenir, about 10 miles north of the Nicaraguan provincial capital of Jalapa. The road between Cifuentes and Los Trojes, where the incident took place, hugs the Honduran side of a barbed-wire fence that marks the border and is in full view of the Nicaraguan side.

The traveler arriving at Los Trojes, which this correspondent visited last November with Torgerson, first sees the settlement from the crest of a hill. The rough town, strung along one dirt street in the manner of a Western movie set, lies in a narrow valley strewn with tobacco drying sheds. The hills on one side lead back toward Honduras. Those on the other side lead onto the northern peak of Nicaragua's Nueva Segovia Province.

The entire area of steep, brush-covered hills has been the scene of heavy fighting during the past three weeks between soldiers of Nicaragua's Sandinista government and Honduran-based Nicaraguan exile guerrillas.

Nearly two weeks ago, the guerrillas took control of El Porvenir. According to Washington Post special correspondent Brian Barger, who traveled to the area last week, Honduran and exile soldiers claimed that the guerrilla offensive had been launched under Honduran military mortar and rifle fire. The Honduran government denied this.

Barger and a correspondent for Newsweek Magazine were fired upon while traveling the same road last week. Other U.S. and European journalists have come under attack recently in the region, but there had been no previous casualties.

According to a leading guerrilla spokesman reached this morning in Tegucigalpa, El Porvenir was retaken by the Sandinistas seven days ago. "The Sandinistas have been operating in that zone all this week," he said, "and for that reason the road has been very dangerous." The guerrillas themselves, he said, do not use the road but tend to operate on foot through the surrounding hills.

The guerrilla leader said that he had been interviewed in Tegucigalpa by Torgerson Monday night and had "warned Dial not to go down there because of heavy activity." During the interview, however, he said Torgerson used the telephone to arrange to rent a car yesterday to drive to the southern region.

Several sources noted that there is a Honduran military roadblock at Cifuentes established to warn civilians against using the road between that point and Los Trojes. They said indications were that the vehicle carrying the correspondents had traveled from Cifuentes to Los Trojes and were on their way back again when the attack took place.

Torgerson, a veteran Los Angeles Times correspondent, served as Jerusalem bureau chief before taking over the Mexico City bureau last year. He was married recently to Wall Street Journal Mexico correspondent Linda Schuster.

In Los Angeles, Times editor William F. Thomas issued a statement saying that "Dial Torgerson worked for the Times for 16 years and never turned in less than a first rate performance. He was an experienced professional and a good personal friend, and he'll be sorely missed by all who knew him."

Cross had worked extensively in Central America during the past several years, primarily on assignment for Newsweek Magazine. One colleage this morning remembered him as "an extremely sensitive, articulate and quiet man who just happened to carry a camera."

Cross was unmarried and lived in Mexico City.