New Delhi: Indian crew members say a stricken cruise ship's alarm sounded very late and they didn't realise the scale of the disaster off Italy's coast until the ship started rolling onto its side.

Four men flown to New Delhi yesterday were the first to return out of 203 Indians who were aboard the Costa Concordia, which slammed into a reef last Friday off the Tuscan island of Giglio after the captain made an unauthorised diversion.

All but one of the Indians aboard the ship were crew members, and one Indian man is among 21 people missing.

Ship waiter Mukesh Kumar said: "The emergency alarm was sounded very late," only after the ship "started tilting and water started seeping" in.

Another crew member who worked in the kitchen also said he didn't realise the scale of the disaster until the ship started rolling onto its side. "The ship shook for a while, and then the crockery stated falling all over," Kandari Surjan Singh said. "People started panicking. Then the captain ordered that everything is under control and that it was a normal electric fault... so people calmed down after that."

House arrest

Another eight Indians who arrived back to India on the same flight continued on domestic flights from New Delhi. Authorities said nearly all are expected back within a few days aboard flights arriving across India.

Capt Francesco Schettino is under house arrest and faces possible charges of manslaughter, causing a shipwreck and abandoning ship, after he left the craft before the more than 4,200 passengers and crew members had safely evacuated. Eleven people have been confirmed dead.