Rescuers in Nigeria have recovered 137 bodies from the wreckage of a passenger plane that smashed into a residential area of Lagos Sunday.

All 153 passengers and crew were killed along with an unknown number of people on the ground.

Among the bodies found are a mother clutching a baby. Rescuers say many of the victims were burned beyond recognition.

The pilot reported engine trouble just before the crash. But presidential advisor Reuben Abati tells VOA (English to Africa) that it is too soon to say what caused the disaster.

“What the president has done, in addition also, is to order an immediate investigation into the cause of the crash. I think what you should do is to await the outcome of the investigation. At this moment everyone is in shock, including the president, and what you have on your hands is a community of people who are grieving.”

President Goodluck Jonathan has declared three days of official mourning. He visited the crash site and promised that such a calamity will never happen again, pledging to improve air safety.

State Department spokesman Mark Toner says the United States sends its deepest condolences to those who lost loved ones in the crash.

The Dana Airlines flight was traveling from Abuja to Lagos when it crashed into a two-story building in a densely populated area, setting other buildings on fire.

Dana Airlines is a domestic air carrier that operates a fleet of Boeing MD-83 aircraft for the hour-long flight from Abuja to Lagos.

Media reports say chaos broke out after the crash, with rescue workers facing large crowds and aggressive soldiers while trying to reach the wreckage in the hunt for survivors.

China says six of its nationals were on the plane.