The Indian navy on Monday towed a shipload of mercenaries back to the Maldives to face justice for their failed coup attempt while authorities in the Indian Ocean republic detained 140 others.

Indian warships took the freighter Progress Light under tow after naval commandos dropped from helicopters to seize the vessel. The 5,000-ton ship was commandeered last Friday by the mercenaries when their coup attempt in the Maldives capital of Male failed.Indian officials in New Delhi said the 46 mercenaries who fled on the arrival in the Maldives of 1,600 Indian paratroopers shot dead four hostages and wounded 15 before they surrendered to the commandos on Sunday.

About 140 Maldivians and Sri Lankans were held for questioning here as officials searched for any remaining mercenaries, whom officials said were recruited in Sri Lanka, hiding in the island chain southwest of southern India.

Maj. Mohammad Zahir of the Maldives National Security Service, who is in charge of the Male investigation, said Sri Lankans, many working in hotels on the holiday islands, were being prevented from leaving while checks went on.

"Because we have not finished searching for Sri Lankan (mercenaries) that are here, we will not let the passengers leave until the search is over," Zahir said.

He said no mercenaries, other than those on the Progress Light, had escaped by sea. A plane had been sent to check reports on Sunday that a second boat had been seen heading south from Male, but nothing was found.

"The search has been called off. As far as we are concerned there is no second boat," he said.

Maldives President Maumoon Abdul Gayoom told reporters at a news conference that the mercenaries would be put on trial, but he declined to say what penalty they would face if convicted.

The mercenaries fled when India sent in the paratroops in response to an appeal by Gayoom for help in putting down the coup, which began last Thursday.

The gunmen hustled 27 hostages aboard the Progress Light and ordered the captain to sail to Sri Lanka. The vessel was damaged by gunfire from Indian forces as it put to sea.

Officials in Male had said seven of the captives were foreigners and included two Swiss and some Filipinos, but the Indian government spokesman did not identify the victims.

The 15 wounded hostages were flown by helicopter to a hospital in Trivandrum, southern India. Among them was Maldives Transport and Shipping Minister Ahmed Mujuthaba, accompanied by his Swiss-born wife Ursula, who was unhurt.

"The commandos did not engage in any action on board the ship . . . there was no resistance," the Indian official said.

The Indian spokesman said the commandos moved in after the frigate Godavari fired warning shots across the freighter's bows and anti-submarine aircraft fired rockets at the vessel.