Police said today that they had interrogated one of the two surviving terrorists responsible for the attack that left three persons dead and 39 wounded yesterday at this city's international airport, but they still had no firm evidence of either the identities or the motive of the attackers.

They said that the questioned man identified himself as Abdel Aziz Merzoughi, 25, and the others as Mongi Ben Abdollah Saadequi, 26, and Ben Ahmed Chaqval, 25, and said that all three had traveled here on Tunisian passports. An independent police investigation established that the three had spent several days prior to the assault in a downtown Vienna hotel, where they had registered as Tunisians under those names.

But police said they remained skeptical of both the identities and the nationality. "He gave us three names, but they might not be real names," said a police official. "He has told us they traveled on Tunisian passports, but no passports have been found."

No documents or papers were found on the men, who reportedly had even cut the labels out of their clothes.

Police said they could elicit no further information from Merzoughi, who was wounded in what apparently was a last-minute escape attempt in which Chaqval was more seriously hurt and Saadequi was killed.

Robert Danziger, director general of the Austrian security forces, today described the terrorists as "suicide commandos" who apparently had no escape route planned, and intended to die in the attack.

CBS television later broadcast what it said was an interview with one of the wounded gunmen. The man gave his name as Mahmoud, and he said all three attackers were members of the main Fatah branch of the PLO. He said they carried out the assault because "we kill Israeli."

The attack took place in a departure area where passengers were checking in for an El Al Israeli airlines flight to Tel Aviv, alongside passengers in line for a charter to Crete. Two passengers were killed, one Austrian and one Israeli. Although government and police officials said yesterday that 47 persons were wounded in the attack, the figure was revised today to 39 without explanation.

Police today identified two American citizens among the wounded. Dr. Peter Lesley, born in Budapest and residing in Munich, was said to be in serious condition in a Vienna hospital. The other American, Donna Kralik, was listed as coming from Maplewood, N.J., and currently an employe of an "international organization" in Vienna. Hospital officials said that Kralik had not been seriously wounded and had been released.

In Washington, a State Department official confirmed that two U.S. citizens were wounded in the attack but refused to divulge their names, saying the victims had not waived their rights under the Privacy Act.

Three Austrian policemen and five Israelis also were among the wounded. Physicians treating the wounded, primarily at Vienna's general hospital, said 18 still were in serious condition. They said one Austrian man had had his leg amputated, and that a 26-year-old Viennese schoolteacher still was unconscious and under intensive care.

Police said they had received a telephone call from a man with a German accent who claimed responsibility for an unknown group he called "Red October," but that they gave little credence to the claim.

Tonight, while airport workers replaced broken glass and plastered over bullet holes, employes who had been in the building at the time of the attack led tours of the assault area. Among the few remaining signs of the attack was a red crayon mark outlining where Austrian professor Ekhart Karner had lain dead.