LAGOS, Nigeria (CNN) -- The pilot of the Dana Air plane that crashed into a densely populated neighborhood in Lagos, Nigeria, radioed that the plane was having trouble just minutes earlier, an airline official told CNN on Monday.
The details emerged as search and rescue crews worked to recover bodies from the wreckage, while authorities searched for the flight data recorders to try to piece together what brought down the plane Sunday, killing all 153 people aboard and at least 10 on the ground.
The death toll will probably rise as crews search the rubble of a two-story residential building that the McDonnell Douglas MD-83 plane struck.
It was unclear how many people were inside the building and on the street outside at the time of the crash, Mohammad Sani Sidi, the emergency management director, told CNN from the crash site.
The pilot declared an emergency as the plane was on final approach to Murtala Muhammed International Airport, and witnesses said it appeared the plane was having engine trouble, said Oscar Wason, Dana Air's director of operations.
Wason identified the pilot as an American, but did not release his name or hometown. The co-pilot was from India, and the flight engineer from Indonesia, Wason said.
Among the dead are six Chinese citizens who were on board the flight, the Chinese Embassy in Nigeria said Monday.
According to witnesses, the passenger plane appeared to be coming in high with its nose up when it crashed, hitting the ground tail first, Wason said.
The flight, bound from the Nigerian capital of Abuja, crashed at 3:43 p.m. (10:43 a.m. ET) in the neighborhood of Iju Ishaga, just north of the airport, according to the Nigerian Civil Aviation Authority.
The crash site was 11 miles from the runway, Wason said.
By Monday morning, crews had recovered more than 80 bodies, including 10 believed to be residents of the building, Sidi said.
The families of the dead were gathered at the airport late Sunday, hours after the crash, and were told there were no survivors, Wason said.
Nigerian President Goodluck Jonathan ordered an immediate investigation into the crash, while declaring a three-day period of national mourning for victims.
Initial rescue efforts were hampered by massive crowds that poured into the streets after the crash, making it difficult for crews and medical workers to get to the wreckage.
Police used batons to beat back onlookers to make way for rescue crews and ambulances, witnesses said.
"There were so many people, you had to push through people to walk," said Pearl Ezeokeke, who was at the crash site.
Femi Green-Adebo, who lives a few blocks from the crash site, said he was home Sunday when he heard a "loud explosion" and ran outside with friends.
"We were trying to see if we could help others," he said. "It was so hot, we couldn't get close because of the fire."
The number of people in the street quickly swelled, and he said he saw police and ambulances trying to make their way through the crowd.
By Monday morning, military police had cordoned off the crash site and workers were sifting through debris.
Charred remains were being pulled from still-smoldering wreckage and placed in body bags set back from the crash site.
Workers also were sifting through the debris for personal effects, trying to match up passports, identification cards and other paperwork to the passenger manifest. Technicians took pictures of cell phones, some partially melted.
A team of Boeing engineers was en route to investigate the crash, Wason said.
The airplane that crashed was 22 years old and was purchased from Alaska Airlines. It underwent a routine maintenance checkup every 200 hours, and it had just been inspected three days earlier, Wason said.
The Nigerian aviation authority has not asked Dana Air to ground its planes, though the airline canceled all its flights Monday as show of respect for the victims of the crash, he said.
Dana Air, which is privately owned and based in Lagos, began operations in 2008.
Nigeria's deadliest air disaster came in July 1991, when all 261 on board a Nigerian Airways airliner were killed when the plane crashed shortly after takeoff in Saudi Arabia.
On Saturday, a Boeing 727 cargo plane operated by Nigeria-based Allied Air from Lagos overshot the runway in Accra, Ghana, and hit a passenger bus, killing 10 people, officials said.
Dana Air set up a 24-hour hotline to provide information about the Sunday crash.
"Our thoughts and prayers are with the families of guests who were involved in the Dana Air mishap," the airline posted on its website. "May the souls of the deceased rest in peace."
Lagos, with a population of more than 7.9 million people, is one of the fastest-growing cities in the world. It is Nigeria's commercial hub.