At least 12 people are dead and dozens missing after a wooden ferry capsized off the coast of Guinea.

The vessel began sinking just minutes after leaving the capital, Conakry on Friday. The accident is reported to have taken place some 700m from the presidential palace.

Officers from the local port of Boulbinet told Al Jazeera that 53 passengers were registered on board the vessel, but they said it was overloaded.

Port officials said 20 people had been rescued and dozens more were missing.

Officials have not said what caused the boat to flip, but one survivor said the seas were rough.

"There was a lot of wind," Mame Asta Bangoura told the Reuters news agency. "We had hardly passed the signal area when the engine stopped again and the boat capsized."

Relatives of the victims, many overcome by grief, gathered near the local morgue, as rescuers combed the surrounding waters desperately searching for more survivors.