Everyone says they did but it’s not so. Neither group took credit for it and Iran and Hezbollah rarely if ever target Jews in the Diaspora. They only target Israeli Jews. Their issue is with Zionism, not the Jews. True, around the same time the Israeli Embassy was blown up in Buenos Aires near the Cultural Center. I’m not yet sure who did that. Iran and Hezbollah may have been behind that, but I’m not sure.
Argentina no longer blames Iran and Hezbollah for blowing up the Cultural Center. Their latest suspects are Argentine neo-Nazis, of which there is no shortage. They probably did it. They’re also suspected in the Embassy bombing, but it’s not clear yet who did that.