U.S. naval forces in the Persian Gulf have destroyed 13 mines in the last six days in a major shipping channel off the coast of Iran's Farsi Island, Defense Department officials said yesterday.

A Pentagon spokesman said the mines "aren't necessarily" new. He said some reports indicate the devices are extremely corroded and may have been in the water for a long period.

"We had reports that there was a minefield here," Cmdr. Francis D. Demast, skipper of the USS Inflict, the mine sweeper that has been used to spot some of the mines, told pool reporters aboard his vessel.

The mines were spotted in the same area where the reflagged Kuwaiti tanker Bridgeton struck a mine during the first convoy of U.S. Navy-escorted ships through the gulf in July.

The two mines most recently spotted were destroyed yesterday, officials said.

Meanwhile, the Pentagon announced that the 19th convoy, three U.S.-flagged Kuwaiti ships escorted by two U.S. Navy warships, was sailing through the gulf toward the Strait of Hormuz yesterday.

China's ambassador to the United States, Han Xu, told the Los Angeles Times yesterday that China has stopped selling Silkworm anti-ship missiles on the international arms market, which he said China cannot control, in order to prevent their diversion to Iran.