The Reagan administration said yesterday it has found nothing "to contradict" official statements from the government of El Salvador that four Dutch television journalists were killed in a fight between government forces and guerrillas.

In private, U.S. officials went beyond their guarded public statements and added that investigation by the American Embassy in San Salvador appears to substantiate the Salvadoran government's claim that the four died in a military encounter and were not the victims of an execution, as some reports have speculated.

However, the officials, who asked not to be identified, acknowledged that they could not tell at this time whether the Salvadoran explanation will be widely accepted. As a result, they said, it is not possible to predict public reaction in the United States and Western Europe or to say whether the incident will cause new controversy about U.S. backing for El Salvador's military-civilian regime.

In issuing statements of regret about Wednesday's killings, the White House and State Department said embassy officials had "conducted a full investigation, and we have no information to contradict the El Salvador government report that the newsmen died in a battle between government forces and the guerrillas."

White House deputy press secretary Larry Speakes, who said President Reagan "deeply regrets" the journalists' deaths, added that the U.S. Embassy would continue "to look into the matter . . . ."

While both Speakes and State Department spokesman Dean Fischer conceded that all the facts are not known, they were careful to qualify their remarks by stressing that they were not trying to cast doubt on the veracity of the Salvadoran armed forces, the ruling junta or its civilian president, Jose Napoleon Duarte.

The question of possible government complicity is especially sensitive now because El Salvador is scheduled to hold elections March 28 for a constituent assembly. Although the United States officially is neutral, U.S. officials are clearly hopeful that the balloting will strengthen Duarte and other political centrists who have promised to bring about stable democratic rule.

Fischer noted, "Nothing I have said should be interpreted as to suggest we lack confidence in the investigations by the government of El Salvador." Separately, Speakes said: "The Duarte government is well aware that we support their efforts to curb extremism of the right or left."

Officials who elaborated privately said the investigation by the U.S. Embassy had been thorough, and had included interviews with most members of the Salvadoran army unit involved in the incident and a viewing of the bodies.

The State Department said late yesterday that the fatal "multiple gunshot wounds" did not appear to have been inflicted at "extreme close range," despite some initial reports to the contrary in El Salvador. The term "extreme close range" was not defined, but an official source said the shots did not appear to have been fired from less than about 25 yards.

According to officials, the tentative U.S. view is that the newsmen's killings, while tragic, resulted from accidentally being caught in a fire fight, and not from a deliberate plot to murder them because of suspected ties to the rebels or attempts to intimidate the large foreign press corps covering the Salvadoran civil war.

But the officials cited no additional evidence to support their opinion. Some admitted that, given the continuing controversy about the regime's human-rights record, the killings could evoke new calls in this country and in Europe for the administration to withdraw its support of the junta and of what many critics charge is a meaningless electoral process in favor of seeking a settlement through negotiations with the guerrillas.