An Iranian national living in Gaithersburg has been arrested and indicted here on charges of conspiring to smuggle prohibited military equipment to Iran, including spare parts for aging U.S. tanks and jet fighters used by Iran in its war with Iraq.

U.S. customs officials said that Kazem Zamani, 42, a former export-import entrepreneur and currently a real estate dealer, was arrested Wednesday at his office in Baltimore and ordered held without bond.

Zamani's arrest marks the latest in a series of arrests of Iranian nationals throughout the United States on charges of conspiring to smuggle equipment as Iran's need for replacement parts increases in its protracted war with Iraq.

At a brief court appearance Wednesday, Zamani was described by federal prosecutors Ty Cobb and Arthur Fergenson as a well-placed operative with assets of more than $1 million in the United States and Iran.

A detention hearing, at which defense attorneys are expected to argue for Zamani's release pending trial, is scheduled for Friday before U.S. Magistrate Paul M. Rosenberg.

A sealed indictment outlining the charges against Zamani was released today by the U.S. attorney's office here after Zamani's arrest.

The indictment charges that between April and November 1984, Zamani conspired with "others unknown" to smuggle three military airborne communications radios, a navigation radio, various radar tubes and an unspecified number of spare parts for U.S. Cobra attack helicopters, tanks, jet fighters and other electronic equipment.

The current Iranian regime under Ayatollah Ruhollah Khomeini seized millions of dollars in U.S. military equipment after the downfall in 1979 of the pro-U.S. shah of Iran, and has been using much of it ever since in its war with Irag.

The United States has prohibited the sale of military equipment to Iran since the Khomeini takeover six years ago, and the need for replacement parts has now generated a covert export business that customs agents say they are trying to stem.

"We've been making cases across the country," said agent Thomas D. Baumgardner, supervisor of the Zamani case.

According to the indictment and customs officials, Zamani put a telex machine in his Gaithersburg home for communicating with dealers providing him the equipment. Agents would not specify who the dealers or other Zamani contacts were.

"The case is still under investigation," Baumgardner said.

"We're still unraveling the evidence," said Leonard Freedman, acting special agent in charge of the Baltimore customs office. " . . .This is a large case. There was a lot of equipment, sophisticated equipment. . . .We're still trying to determine if any of it got to Iran."

If convicted, Zamani could be sentenced to five years in prison and fined $125,000.