The Swiss ambassador in Tehran, who also represents US interests, was called to the Foreign Ministry on Tuesday to hear Iran's protest over two recent rulings by US courts against Tehran.
The US Supreme Court has ruled that nearly $2 billion from Iran's frozen assets must be turned over to the families of American soldiers who lost their lives in terrorist attacks the US blames on Iran, including 241 in the 1983 truck bombing attacks in Beirut.
Tehran has also been convicted by a US court of involvement in September 11, 2001, terrorist attacks in New York.
Julio Haus was handed two notes of protest over the rulings, IRNA reported.
Haus said he would immediately inform the US State Department and report back to the Iranian Foreign Ministry.
Foreign Ministry official Mohammad Keshavarzadeh denounced the US moves as a "blatant" violation of international law on the judicial immunity of governments.
He rejected the allegations over the New York incident as "unfounded" and "ridiculous", noting that there is no evidence pointing to a role by the Islamic Republic or its nationals.
The Swiss Embassy has been handling US interests in Tehran since the United States and Iran broke off diplomatic ties after the 1979 Islamic Revolution.
