In an interview with the Jewish News Agency (AJN), Lieberman said: "We certainly know that Iranians were involved in the attacks."
He said he regretted that Israel wasn't able to prevent the deadly attacks against AMIA, the Jewish community center, and the Israeli Embassy.
"We regret that Iran was a step ahead us. The Islamic republic has been operating in South America for many years. We know that they are involved in the terrorist attacks," he later told a press conference.
Lieberman said he was awaiting a report from Argentinean judicial authorities on their investigation into the attacks.
"Now I'm waiting for the final report by the judge who hears the case in Argentina, the results of the warrants of arrest given to Interpol and the results of the research regarding Hizbullah's activities in the region," he said.
Lieberman said at the start of his four-day trip to Argentina on Thursday that "Iran is the biggest sponsor of world terror organizations such as Hamas, [Islamic] Jihad and Hizbullah."
"If Iran would achieve nuclear capacity, we'll see a crazy nuclear-armed race in our region that will be a threat not only to Israel but to the rest of the world," he told reporters in Buenos Aires.
Argentina is the second stop after Brazil of a 10-day tour of four South American nations aimed at staunching Iran's growing influence in the region.
Lieberman met with Argentine Foreign Minister Jorge Taiana to discuss preparations for President Shimon Peres's visit in November, according to a Foreign Ministry statement.
Argentina is home to the largest Jewish community in Latin America. Argentine prosecutors say Iran and Hizbullah were behind the 1994 bombing of AMIA in the city that killed 85. Iran has denied involvement.
There was also another bomb attack in 1992 against the Israeli Embassy in Buenos Aires that killed 29 people. None of the attacks has been solved.
During a Wednesday meeting with Brazilian President Luiz Inacio Lula da Silva, Lieberman asked Latin America's biggest nation to use its influence to help halt Iran's nuclear program. Lieberman noted that Brazil has good ties both with Muslim countries and with Israel.
"Its objective is propaganda against the good relations that exist between Iran and Latin America," Edrisi said.