More than 100 people have drowned and more are missing after a boat carrying them down the River Niger in south-western Nigeria capsized, authorities say.

The vessel was carrying more than 300 passengers travelling from Kwara state to Niger state after a wedding ceremony.

Search and rescue efforts are ongoing to find more victims, officials said.

The boat capsized after it crashed into a tree, a traditional local ruler said.

"Dozens of people were feared killed and many others [are] still missing", a statement from the Kwara state Governor AbdulRahman AbdulRazaq said on Tuesday.

The Emir of Patigi, Ibrahim Umar Bologi II - the traditional ruler of the area where it happened - said more than 150 people had died.

He told journalists that river waves overtook the boat and forced it to crash into a tree that had washed into the river, causing the boat to capsize.

A Kwara state police spokesman told AFP news agency the death toll was likely to rise as search and rescue efforts continued.

Kwara state governor Mr AbdulRazaq gave his "heartfelt condolences" to the victims' loved ones - and said rescuers were continuing to search for survivors.

River accidents in this part of Nigeria are common.

People who live in the villages bordering the River Niger, which runs through the centre of the country, often use the river as it can be faster than roads, which are often poorly maintained and dangerous due to the presence of kidnapping gangs.

However, boat operators often overload their rickety vessels in a bid to earn more money.