Iraq's use of a Silkworm missile to go through the defences of Kuwait early on Saturday morning has boosted sales of an antibiotic.

Fearing that the next attack could be launched with a warhead filled with chemical or biological agents like anthrax, Kuwaitis are stocking up on Ciprofloxacin.

Taking Ciprofloxacin does not remove the need to wear a gasmask, but doctors say it is 80 per cent effective.

A 500mg tablet costs nearly a dollar and experts recommend taking at least 60 tablets over 60 days following a confirmed anthrax attack.

There was no air raid siren before the attack, which took place shortly before 0200 hours local time. The ear-shattering explosion sent people scurrying to their bomb shelters.

The missile fell off the coast of Kuwait, near a shopping mall. Its pieces were strewn everywhere and the main cinema and glass doors of the shopping centre bore the brunt of the attack. The stench of the burning metal was present hours later.

Though the waterfront mall shuts at 2100 hours, its cinema is open till early morning. The centre boasts of a huge marina and more than 100 shops and restaurants.

The mall is opposite a fish market and just a stone's throw away from the foreign ministry and the Seif Palace, the seat of Emir Sheikh Jaber al-Ahmad al-Sabah.

The Silkworm is a crude cruise missile, which is most effective against ships across flat watery surfaces.

The one that was fired on Saturday has been the most effective of the 12 missiles that Iraq has fired on Kuwait and the US-led coalition forces in the oil rich emirate.

The rest have either fallen on the desert or have been intercepted by Patriot anti-missile batteries.

But the Patriot has proven to be far less effective against the low flying and less predictable trajectory of the C802 Silkworm, which is equipped to carry one tonne of conventional high explosive, but can be easily modified to carry chemical or nuclear warheads.

"We know the Iraqis have Silkworms and there is evidence that they have used them," US Army spokesman Lieutenant Colonel Larry Cox told rediff.com "We don't know where they have been used or how many times."

A solitary jogger who saw the incoming missile said it was oval-shaped with English and Arabic writings on the side.

Lt Col Cox said the Silkworm is one of four or five types of missiles with the Iraqi army. He said this does not contradict earlier statements that southern Iraq has been militarily secured.

"Southern Iraq is secure in the sense that we have secured our military objectives," he esaid. "That does not mean its safe or that the Iraqi military or militia death squads have been eliminated."