US President Donald Trump has vowed to help end "vicious and violent" conflicts on the African continent.

"Africa right now has got problems like few people would even understand," he said at a Nato summit press conference.

"It is so sad, it is so vicious and violent," he said, promising that his goal was to build up the US military and bring peace to the world.

The US is active in counter-terrorism operations and training African troops to fight jihadists in the Sahara.

The 72-year-old US leader was speaking after a two-day summit in Brussels, where he said Nato allies had agreed to increase their military spending.

'We want peace in Africa'

His comments about Africa's problems came after a Tunisian journalist expressed gratitude for US efforts in North Africa, where various Islamist militant groups operate.

The president said the continent had "got things going on there that nobody could believe in this room".

"If you saw some of the things that I see through intelligence - what's going on in Africa - it is so sad, it is so vicious and violent," he said.

"We want peace for Africa. We want peace all over the world. That's my number one goal - peace all over the world and we are building up a tremendous military because I really believe through strength you get peace."

Mr Trump said that the US was "going to have a military like we never had before".

But his remarks have drawn some criticism on social media - and come seven months after he was alleged to have used the word "shithole" to describe African nations. He denied that he was racist.

Commentators on Twitter suggested he was reinforcing Western stereotypes of the continent, with one Kenyan journalist implying he was naive not to realise that Africa had 54 countries.

There are 54 countries in Africa! So which Africa is this has got “problems like few people would understand.”?
Trump vows to end 'vicious' African conflicts https://t.co/HncEUfL2z1 via @BBCNews

— Elizabeth Merab (@emcleans) July 12, 2018

Another tweeter suggested that an American school shooting was as vicious as any conflict in Africa.

Vicious. Violent. Sad. Trump reinforces Western stereotypes on Africa.

— Robyn Dixon (@RobynDixon_LAT) July 12, 2018

BBC Africa correspondent Alastair Leithead says the US has about 7,000 military personnel in Africa and 34 individual bases or staging posts across the continent - and probably many more secret facilities.