* Crash kills 147 passengers and 6 crew
* "Horrific moment" says Lagos state governor
* President Jonathan declares 3 days of mourning
By Hannington Osodo and Oludare Mayowa
LAGOS, June 4 (Reuters) - Nigeria recovered bodies and searched for clues on Monday after an airliner crashed in a residential area of Lagos overnight, killing all 153 people on board and prompting the president to declare three days of mourning.
President Goodluck Jonathan visited the crash site in Nigeria's commercial hub and saw rescuers working amid the smouldering, ash-covered wreckage of the McDonnell Douglas MD-83 flown by privately owned domestic carrier Dana Air.
Jonathan ordered an investigation into how the plane crashed into the iron roof of an apartment block in the residential suburb of Agege.
Search teams found what they believed to be the plane's "black box" flight recorder, national emergency services chief Yushua Shuaibu told Reuters.
Jonathan, who arrived in an armoured convoy with Lagos state governor Babatunde Fashola, got out and walked the last few metres to the crash site on foot in his traditional Nigerian kaftan and skull cap.
"This particular incident is a major setback for us as a people ... Investigations will have to be done thoroughly to ascertain what was the cause of the crash," he told reporters.
The airline said on Sunday 147 people had been killed but in a list published overnight there were also six crew members on board, taking the death total to 153. An unknown number of people may have been killed on the ground.
An official at the airline who could not be named said the pilot was an American, Captain Peter Waxtan, and the first officer an Indian named Mike Mahendra.
"They're still busy recovering bodies. I believe some people were killed on the land as well as on the plane, though we don't yet have a precise idea of numbers," said Tunji Oketunbi, a spokesman for Nigeria's Accident Investigation Bureau.
Oke Osanyintolu, head of the Lagos State Emergency Management Agency, told Reuters at the scene that 80 bodies had been pulled out by about 12:30 p.m. (1130 GMT). A crane was helping to clear away some of the debris.
"This is really a horrific moment for us here and we sympathise and give condolences to all the victims and families," said governor Fashola.
A source at Dana, who asked not to be identified, said the plane was manufactured in 1983.
"ONLY A MATTER OF TIME"
Though large curious crowds were still gathering around the scene, they were more controlled than on Sunday when thousands thronged the streets, hampering emergency services.
"This is a crash site, it is an investigation site and we should keep our distance and allow the first responders to do their work," Fashola told crowds.
Among the dead was the spokesman for the Nigeria National Petroleum Corporation, Levi Ajuonuma, according to a passenger list released by the airline. Ajuonuma was also the only de facto spokesman for the oil minister in OPEC member Nigeria, Africa's biggest crude producer.
"(There are no) words to express our pain and grief. It is saddening, it is simply too much."
A French woman was among passengers killed, said Yamina Benguigui, France's Junior Minister for French Nationals Abroad. "I would like to offer my sincere condolences to her family," she said.
"We still don't know the numbers killed on the ground," said Shuaibu. "They were scattered in different places and we have yet to differentiate the passengers from others."
Air crashes are not uncommon in Nigeria, Africa's second biggest economy, which has had a poor airliner safety record.
"To be fair, the number of similar incidents has reduced in recent years," said Samir Gadio, London-based analyst at Standard Bank, which has a big operation in Nigeria.
"However, it was only a matter of time before something tragic happened. Security is poor on domestic flights, some of the planes are from another age, maintenance is questionable."
Residents who witnessed the crash were still in shock.
"The plane touched this tree here," said Immanuel Shoyimi, a businessman, gesticulating towards a large mango tree in a nearby backyard.
"Then it entered into that compound. Boom! I watched for five minutes, not knowing what to do. I wanted to call someone but I didn't know who to call."
The roof of his house was also scraped by the plane, he said.
"The shock was too much. Before I knew it I heard two blasts from the plane."