About a dozen gunmen dressed in police or military uniforms forced their was into the home of Walter Klein, a high official of the Argentine Economics Ministry, early this morning, killed two of his bodyguards and then bombed the house while Klein and his family were still inside.

The incident was similar to earlier assassinations or attempted assassinations of prominent government figures here that are believed to have been carried out either by leftist Montonero guerrillas or by military security units posing as guerrillas. These units are said to be commanded by officers in disagreement with the economic and political policies of the military government headed by president Jorse Videla, a retired general.

[A message delivered to news agencies later claimed responsibility for the Montonero group, which the military said it had wiped out after seizing power in 1976].

Details of today's incident -- and assessments of who might have been responsible -- kept changing through the day. Witnesses said the gunmen were dressed in Buenos Aires Province police uniforms and reported hearing rifle fire.

Initial police accounts said there was no shooting but later, police reported that there had been machine gunfire and that two of Klein's four bodyguards were dead. Police also said the attackers, including several women, were dressed in green military fatigues and wore black berets.

While the exact details of the incident remained unclear, there was little doubt that Klein was targeted because of his position of chief assistant to Economy Minister Jose Martinez de Hoz, who has Videla's support but whose policies are extremely unpopular both inside and outside the divided military establishment.

Last year, another of Martinez de Hoz's top assistants, Miguel Padilla, was assassinated in front of his home by gunmen. The Marxiest-Peronist Montoneros later claimed responsibility for shooting Padilla.

The home of another civilian member of Videla's government, Ricardo Yofre, was bombed several times in 1977 and 1978 before he quit as one of the president's chief political advisers. It generally is belived that Yofre's house was bombed as a waring to Videla by a dissident military faction.

Rumors circulated here that a high civilian government official would be kidnaped and assassinated by military units posing as Montoneros during the recent visit of the Inter-American Human Rights Commission. The idea was to demonstrate that the military's war against guerrillas is justified by continuing terrorism, according to the rumors. Yet nothing happened.

Two months ago, Mario Firmenich, an exiled leader of the Montoneros, said in Managua, Nicaragua, that his followers would step up their acitivities inside Argentina to topple the 3 1/2-year-old military government. There has been some evidence of increased Montonero activity since then.

Whoever was responsible, the attack on Klein's house was viewed here as a setback for Videla, who walks a tighrope between keeping the guerrillas in check and persuading hard-line generals that the methods they have used against suspected Montoneros -- sudden disappearances, probable torture and death -- are no longer necessary.

The divisions between Videla and the hard-line generals on human rights issues have become more public in recent days. Newspapers here today corroborated earlier diplomatic reports that Videla, his justice minister and all five members of the Supreme Court threatened to resign Monday evening after the country's top generals allegedly voted 6-3 against releasing newspaper publisher Jacobo Timerman.

The generals reportedly changed their minds Tuesday morning only after Gene. Roberto Viola, commander-in-chief of the Army and a member of the ruling junta, informed them of Videla's threatened resignation, which would have caused serious political instability.

Most observers here did not think that today's bombing was directly related to the Timerman decision even if the bombing was carried out by the police or military units.

Instead, it appeared to be aimed at the economic policies of Videla and Martinez de Hoz, who has tried to bring about a slow "rationalization" of the economy by opening the country to imports and thereby forcing local producers to become more efficient as a result of increased competition.

These policies, in part formulated by Klein, a soft-spoken, brilliant economist educated in Britain, are unpopular with businessmen because their profits have been shrinking, with unions because the government has made strikes illegal and with the general public because their standard of living has been reduced.

Inflation has continued at 170 percent a year.