A shipment of Chinese-made Silkworm missiles is believed to have arrived at an Iranian port from North Korea on Monday, according to administration sources.

About half a dozen missiles and a launcher were spotted on the dock of a North Korean port where the Iranian merchant ship Iran Bayan was loading two weeks ago, according to intelligence reports.

When the ship sailed, the missiles and equipment were no longer on the wharf, indicating that they had been loaded on the ship, the reports said.

U.S. intelligence sources monitored the ship as it sailed from North Korea into Bandar Abbas, sources said. They said intelligence sources were waiting to see whether the equipment is unloaded.

North Korea has been a transfer point for Chinese shipments to Iran. North Korea also sells arms directly to Iran. U.S. officials said they don't know whether the silkworms that arrived Monday were sold to Iran by the Chinese or were being resold by the Koreans.

U.S. officials reported two weeks ago that they think that China is sending Iran more Silkworm missiles or a newer, more deadly cruise missile that could be used in escalating the "tanker war" with Iraq in the Persian Gulf.

Intelligence sources spotted crates of the new missiles on docks in North Korea but lost track of that shipment, the officials said. Administration officials said yesterday that they think that those missiles arrived Monday.

Silkworm missiles have been considered a major threat to shipping in the gulf where the U.S. Navy has been escorting American-flagged Kuwaiti tankers since July.

An Iranian Silkworm attack on an American-flagged ship in a Kuwaiti harbor prompted U.S. retaliation last October in which the Navy destroyed Iranian platforms used in the gulf for miliary operations.

U.S. officials have criticized China harshly for selling Silkworm missiles and other antiship weapons to Iran and decided late last year to delay transfers of high-technology items to China unless it stopped such shipments.

China is Iran's largest supplier of weapons and is thought to have sold Iran about 100 Silkworms in recent years, according to administration sources. China also is a major supplier for Iraq, which has been at war with Iran for seven years.

Iran has launched several of the missiles against Iraqi land targets and has hit two ships in Kuwaiti waters in recent months. Kuwait is a close ally of Iraq.