An American judge has ruled for the first time that Iran was responsible for the 1992 bombing of the Israeli Embassy in Argentina. Judge Ellen Huvelle, who sits in Washington, ruled Monday that Tehran must pay about $63 million to the family of an Israeli diplomat who was one of 29 killed in the Buenos Aires attack. She said the bombing was carried out by Hezbollah and could not have taken place without assistance from Iran.

“While it is unclear whether defendants actually provided the bomb that was used in the attack, they had knowledge of the plot, and they provided the support that allowed Hezbollah to carry out the embassy bombing,” the judge wrote.

Judge Huvelle awarded $30 million in emotional damages and about $3.7 million in lost earnings to the widow, parents, children, and siblings of David Ben-Rafael, who was 43 when he was killed. Ben-Rafael was born in America and most members of his family are Americans, but he gave up American citizenship when he entered the Israeli foreign service. The judge almost doubled the total award by granting the family interest accrued back to the date of the bombing.

“We’re actually tremendously pleased because it upholds the principle that you cannot engage in this kind of behavior if you are a sovereign,” a lawyer for the family, Emil Hirsch, said. He acknowledged that it would be tough to recover the judgment, since Iran already owes about $9 billion for similar awards in terrorism cases.

“I am a realist,” Mr. Hirsch said. “Barring some act of Congress, we are probably not going to collect this in the United States soon. However, we are very serious about pursuing collection of this judgment in the international arena.”

Iran did not defend itself against the lawsuit.