Austrian Interior Minister Karl Blecha said today that he has "ruled out" responsibility by Yasser Arafat's Palestine Liberation Organization for Friday's terrorist attack at this city's international airport.

Blecha said the government still was investigating the possibility that the attack was launched by a breakaway PLO group headed by Abu Nidal, but had not come to any definite conclusions.

Another police official said today, however, that "we believe, we think, that our two terrorists belong to Abu Nidal." Three men were involved in the attack. One was killed in a shootout with police and two were wounded and remain hospitalized.

The attack on passengers checking in for an Israeli El Al Airlines flight to Tel Aviv killed two travelers and wounded 39.

Abu Nidal, a bitter foe of Arafat, was held responsible for the 1981 murder here of the head of the Austro-Israeli Society, Heinz Nittel, and for a bombing at a Vienna synagogue later that year that killed two persons. These previous attacks, Blecha said, "must be taken into consideration."

But police here would not say what evidence has led them to rule out a PLO role and their comments thus far have brought criticism that Austria, which has good relations with the mainstream PLO, is over-eager to clear Arafat. Austria was the first western country to allow the PLO to open a permanent office in its capital, and former chancellor Bruno Kreisky was the first western leader to receive Arafat formally.

An Israeli diplomat here suggested today that Austrian officials have a vested interest in "whitewashing" Arafat at the expense of the Abu Nidal breakaway group. Blecha, who spoke in a television interview tonight, denied a whitewash, and said, "We are exploring everything to find the truth."

Although police now have interviewed the less-seriously wounded of the two surviving terrorists twice, and an investigating judge spoke to him through an Arabic-speaking interpreter this afternoon, they have released virtually no details of what he has said and insisted that he has remained largely uncommunicative.

He identified himself as Abdel Aziz Merzoughi, and offered names for the other two, but police repeatedly have said they believe he may have been lying.

"It's very possible that what they are saying is not reality," Austrian Security Chief Robert Danzinger said in an interview. "It's difficult to believe anything in this case."

The question of whether the Arafat-led PLO or the Abu Nidal faction carried out the attack is considered vital because Israel has threatened to retaliate against those responsible.

The issue has been clouded here by an interview with Merzoughi by CBS television news yesterday. In his hospital room, Merzoughi, who seemed to have a poor command of English and gave largely monosyllabic replies to questions in English, said, "Yes" when asked whether he was "from the PLO." Asked from where he had received his instructions, he rubbed his eyes and said only, "I am Fatah."

"Our interpretation," said a police official, "is that we don't know if the terrorist really understood the question" or if the answer was understood as it was meant. The title of "Fatah" is disputed between Arafat and the Abu Nidal faction.

In addition to being overall PLO chairman, Arafat heads Fatah, the largest of several divisions under the PLO umbrella. The official name of Abu Nidal's group, however, is the Fatah Revolutionary Council.

Danzinger expressed anger that the CBS reporter and crew were able to enter Merzoughi's room yesterday at Vienna's general hospital. He said the interview had been authorized by a junior official without his knowledge.

Merzoughi was transferred to the police hospital today. Police sources said that doctors had not authorized interrogation of the second wounded terrorist, identified by Merzoughi as Ben Ahmed Chauval. Merzoughi said the dead man was Mongi Ben Abdollah Saadaoui.

Danzinger said police had determined that the three men for some time just before the attack had stayed in two Vienna hotels, and not the one hotel reported yesterday.

Danzinger also said a Tunisian passport number had been obtained from at least one of the hotel registers, and that "we are trying to get answers from Tunisia" about it.

In his initial interrogation yesterday, Merzoughi told police that the three entered Austria on Tunisian passports, but later threw them away. No documents were found on the men.

In the CBS interview, Merzoughi said they were Palestinians from Lebanon. He responded "yes" when asked if the terrorist attack had been launched in the name of Palestine. Asked why they had done it, he said, without explaining, "Because it is Israel. We kill Israel."