The mainly Syrian migrants were bundled off the Blue Sky M when it arrived in Italy in the early hours of the morning after it was first spotted near the coast of Corfu.
Greece sent its navy and coastguard with a military helicopter to the scene on Tuesday in response to an alarm call about a possible incident on the Moldovan-flagged ship.
Italian officials were airlifted onto the Blue Sky M after it left Greek waters to check it could navigate safely. The coastguard said there were 970 people on board when the ship arrived at the small port city of Gallipoli.
Emergency workers hurried the migrants out of the freezing cold into a hospital tent and onto coaches when they arrived. After an erroneous Red Cross report of four deaths earlier, officials said no one was known to have died.
Greek state television reported on Tuesday that the alarm had been raised because armed men were on board, but the defence and shipping ministries did not confirm this.
The Red Cross said the ship, which reportedly set off from Turkey, had apparently been abandoned in the Strait of Otranto that separates Italy from Albania.
“The ship was abandoned by its crew in open water,” Red Cross spokeswoman Mimma Antonagi said. “If (Italian officers) had not gone on board, it would have crashed into the coast.”
Local prosecutors have impounded the Blue Sky M as part of an investigation into the incident and arrested a Moldovan man who arrived on the ship and was identified by the migrants as one of the people smugglers arranging their passage, a judicial source said.
Civil war in Syria and anarchy in Libya have swelled the number of people crossing the Mediterranean in rickety boats this year. Many of them paid smugglers $1,000-$2,000 to travel.
The United Nations refugee agency says 160,000 seaborne migrants arrived in Italy by November 2014 and a further 40,000 in Greece. Thousands more have died attempting the journey.
Italy is due to close its Mare Nostrum maritime search and rescue mission definitively at the end of December, partly due to popular concern over the 114 million euro ($138.25 million) bill the mission racked up in its first year.
Human rights groups have warned that closing Mare Nostrum would endanger more lives in the Mediterranean. ($1 = 0.8246 euros) (Reporting by Isla Binnie, additional reporting by Vincenzo Damiani in Bari, Editing by Angus MacSwan)
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