DUBAI, UNITED ARAB EMIRATES, AUG. 6 -- Iran stepped up its psychological war against the United States today, extending naval maneuvers in the Persian Gulf for an additional day as a convoy of American ships made preparations to steam into the gulf.

Word of the one-day extension of the maneuvers, which started Tuesday under the code name "Martyrdom," was broadcast by Tehran Radio.

In the first detailed Iranian account of the exercises, the broadcast said Revolutionary Guard units were rehearsing attacks on shipping, using vessels equipped with cannon "as well as remote-controlled vessels packed with explosives and pilotless planes."

The broadcast appeared to be a thinly veiled warning to the United States, which Iran has threatened to retaliate against because of last week's violence in Mecca. Iran has accused Saudi Arabian authorities of massacring Iranian pilgrims in Mecca at the behest of the United States.

Iran has warned foreign shipping and warships to stay clear of Iranian territorial waters for the duration of the naval exercises.

A task force of U.S. warships has gathered off Khawr Fakkan, a port on the Gulf of Oman just outside the Strait of Hormuz, to begin the second convoy of reflagged Kuwaiti shipping.

U.S. military officials have delayed the reflagging for up to a week, awaiting mine-sweeping and other protective equipment, according to Defense Department sources.

A London newspaper, the Independent, reported that Iran is quietly appealing to Kuwait to suspend the reflagging of its tanker fleet, offering in exchange a guarantee that Kuwaiti ships would not be attacked. The newspaper quoted unidentified sources as saying an Iranian delegation has been in Kuwait this week for discussions on the offer.

It quoted the sources as saying the Iranian government, despite its aggressive public stance toward the United States, is alarmed at the prospect of a direct confrontation with the Americans. The paper, which takes an independent political line, said Kuwait's response to the offer was not known.

In Washington, however, Secretary of State George P. Shultz said that as far as he knew "there is nothing to the reports."