Police Superintendent Charlie Barry said four of the six survivors were hospitalized in serious condition, chiefly with broken ribs and limbs, while two others escaped with minor cuts and scrapes.
"Two actually walked out, miraculously," he said.
Among the dead on the flight from Belfast, Northern Ireland, were a senior Belfast accountant, the deputy master of Belfast Harbor, two pilots from Britain and Spain, and a relative of Irish President Mary McAleese.
"I am especially conscious of the pain being experienced tonight by all of the bereaved as one of the deceased was Brendan McAleese, my husband Martin's cousin," said McAleese, Ireland's ceremonial head of state.
"No words can ease their pain," she said, referring to the families of all six dead. "But I hope they draw some small comfort from knowing that our thoughts and prayers, both here and in homes throughout the country, are with them at this darkest hour."
The Irish Aviation Authority responsible for running the airport said the fog was so thick that air traffic controllers in a nearby tower could not see the crash, only hear it.
Thursday's crash was the deadliest in Irish aviation since 1968, when an Aer Lingus flight from Cork to London crashed into the Irish Sea, killing all 61 on board.
Prime Minister Brian Cowen, who flew by helicopter to the scene Thursday, said it was the first time that a commercial aircraft had crashed and caused fatalities when landing at an Irish airport.
The Irish Aviation Authority said the aircraft - a twin-engined turboprop leased to Isle of Man-based airline Manx2.com and operated by a Barcelona-based company called Flightline BCN - aborted two attempts to land before crashing on the third try.
Authority chief executive Eamonn Brennan said prevailing winds were weak and not a factor, while Cork frequently suffers from fog.
Brennan said the pilot first tried to land from the south but pulled up, then immediately tried again from the north but aborted that run too. He said the pilot waited another 20 minutes, then tried the southern approach again - but landed either just short of the tarmac or in the grass to the right.
"The visibility was so bad that the tower was not in position to see the aircraft when it impacted," he said.
Aviation expert David Learmount criticized the pilots' decision to attempt three landings in fog, describing the visibility as "just not good enough."
"It's not normal to try a third time to make a landing. After two goes, you normally try to go to your designated diversion airfield," said Learmount, operations and safety editor of Flight Global magazine.
Television footage of the crash scene showed that the aircraft's wings were shorn off and the entire front half of the fuselage was crushed. The wreckage came to rest upside down with the landing gear extended and intact. The tail was protruding upward, with comparatively little external damage evident to the rear seating area of the aircraft.
Barry said emergency firefighters doused a fire in one of the plane's engines within three minutes. He said those killed were predominantly in the front half of the aircraft.
The aircraft was a Fairchild Metroliner, a 19-seat turboprop aircraft manufactured in San Antonio, Texas, in 1992. Barry said it was carrying 10 adult passengers and two pilots.
Cork Airport's runway was closed and all incoming flights diverted to Shannon, the larger airport in southwestern Ireland.
Irish airline Aer Lingus said it diverted 16 flights to Shannon and canceled four others. Ryanair diverted five and canceled two.
The Catholic bishop of Cork, John Buckley, went straight to the airport terminal to comfort relatives of the dead and injured planning to collect loved ones from the flight. Buckley said he "offered them the prayers of all Irish people at this sad time."
Later, the Irish prime minister met survivors in Cork University Hospital. Cowen said he talked mostly with the two who walked away from the crash, including Donal Walsh, a volunteer for the International Fellowship of Evangelical Students in Ireland who had just attended a Christian conference in Belfast.
Manx2.com was founded in 2006 and operates flights linking Ireland, Britain and the Isle of Man. It opened the Belfast-Cork route six months ago.
Manx2.com describes itself as a "virtual" airline that doesn't own its own aircraft or provide its own crews, but instead uses several aircraft-leasing companies. On its website it describes the Flightline-leased Metroliner that crashed as fast, comfortable and offering a window seat to every passenger.
Fairchild ceased manufacturing the Metroliner in 2001. Fairchild - best known for manufacturing the A-10 Thunderbolt "Warthog" ground-attack aircraft for the U.S. Air Force - was taken over by M7 Aerospace in 2003.
Cork Airport, http://www.corkairport.com/tns/home.aspx
Manx2.com air fleet including crash plane, http://bit.ly/iamJhA