A Spanish supertanker, hit by an Iraqi raid last week, exploded Tuesday and shipping executives said at least nine crewmen from a nearby tugboat were missing.

Meanwhile, the Iranian tanker Bisoton was identified as the latest victim of stepped-up raids by Iraq on its foe's oil shipping lanes.The blasts Tuesday partially sunk the 235,000-ton Barcelona and scuttled a Norwegian-flag salvage tugboat that was alongside, according to shipping executives, who spoke on condition of anonymity.

Nine crewmen from the tug, the Scan Partner, were missing and feared dead after the explosions, the executives said.

The sources said bodies were washing up on the rocks and Iranian army personnel were trying to recover them. They did not know whether the bodies were those of the tugboat crew or of others missing in Saturday's raid on Iran's Larak island terminal in the Strait of Hormuz.

An estimated 22 seamen were killed or remain unaccounted for in the attack in which five ships were hit by Iraqi jets, according to salvage executives.

In additon to the 235,000-ton Barcelona, the ships hit were the 564,739-ton Liberian-flag Seawise Giant; the 457,841-ton British-flag Burmah Endeavour; the 152,004-ton Cypriot-flag Argosy; and the 231,712-ton, Iran-owned Khark.

International tankers call at Larak to pick up oil cargoes brought down the Persian Gulf by Iran's fleet of shuttle tankers.

In the latest raid, Lloyd's said the 112,445-ton Bisoton was attacked by Iraqi warplanes Monday off the Iranian coast. It said a fire broke out in the engine room but was quickly extinguished.

Lloyd's did not say whether there were casualties aboard the Bisoton, but it had referred earlier to information that 10 seamen were killed in an Iraqi raid on a tanker Monday.

It did not link these casualties with the Bisoton but there were no other attacks reported Monday.

The Baghdad High Command reported Monday that Iraqi jet fighters raided "a large maritime target" off the Iranian coast, its usual terminology for an Iranian tanker.

Baghdad's avowed aim is to throttle Iran's oil exports, the backbone of Tehran's economy, and force Iran to accept a negotiated settlement in the 71/2-year-old war.

Iran has responded to Iraq's attacks by raiding neutral commercial shipping.

Also Tuesday, the U.S. Navy said it planned to drop a wreath in the waters of the central gulf to mark the first anniversary of the Iraqi air attack on the frigate Stark, in which 37 Americans were killed.

Navy officials said the ceremony would be conducted by a chaplain, aboard either a U.S. warship or a helicopter. There was no word on what time it would take place.