U.S. submarines are blasting Tomahawk cruise missiles at Iraq, possibly over friendly territory, from beneath the Mediterranean and Red seas in the first such combat use of the weapons, Pentagon sources say.

Although the sources would not describe the missiles' routes Thursday, firing the computer-guided, low-flying weapons from either sea means the weapons could be flying through Turkish, Egyptian, Israeli or Syrian airspace.The development in the war against Iraqi leader Saddam Hussein amounts to "the first use of American submarine-launched missiles in a combat environment," said one source, who like others spoke on condition of anonymity.

"There have been multiple launches" of Tomahawk missiles from the submerged subs over the past several days, a second source said.

A senior operations officer refused to comment on the number of sub-launched missiles. "We don't discuss that weapon system," Marine Maj. Gen. Martin Brandtner said briskly at a Pentagon briefing Thursday.

The Pentagon said Thursday that some 230 cruise missiles have been fired in first week of the military operation - primarily from larger surface warships such as battleships and destroyers in the Persian Gulf and Red Sea,

Asked how many submarines were involved in targeting Iraq, one source replied: "Let's just say a few."

There are 123 submarines in the Navy's fleet - 89 attack subs and 34 ballistic missile submarines. Attack subs usually accompany most carrier battle groups, and six aircraft carriers have been detailed to the Middle East for Operation Desert Storm.

The commander of the U.S. naval force in the Red Sea, Rear Adm. Riley Mixson, disclosed earlier this week that one submarine had fired a cruise missile as part of the campaign against Iraq.

Submariners are dubbed the "Silent Service" because of their ability to roam undetected and hunt their prey at will. They prefer to have their activities kept out of the limelight.

"It's ingrained in submariners. Their effectiveness depends on them being `the big question mark,' " said one Pentagon official.

Much fanfare usually accompanies the activities of surface craft, such as battleships, meaning an opponent can prepare for their entry into combat.

But submarines stay out of sight, deliver their weapons and leave without detection. "A lack of fanfare is a measure of submariners' success," the official said. "The only time anyone would know it is there is when the Tomahawk breaks the water."

Making use of the pinpoint accuracy of the relatively slow-flying Tomahawks, the subs have been directing the missiles against strategic targets, such as suspected chemical weapons facilities, the sources said. With a conventional warhead, the missiles have a range of about 700 miles.

The entry of submarine-launched missiles into Desert Storm "just gives Saddam a new threat to worry about," one source said. Missiles "are now coming at him from the north as well as the south."