This is the Global News podcast from the BBC World Service.

I'm Jeanette Jaliel and in the early hours of Tuesday the 28th of January, these are our main stories.

US tech shares have fallen sharply on Wall Street in response to Chinese advances in AI,

threatening the dominance of big American firms.

The United Nations says there's no doubt Rwandan troops are supporting M23 rebels

who are seizing the Congolese city of Goma.

Holocaust survivors have marked the 80th anniversary of the liberation of the Nazi death

camp at Auschwitz.

Also in this podcast, HMS Agincourt, would instead be known as HMS Achilles.

We'll tell you why the changing of the name of a British submarine has caused an outcry.

We begin in the world of big tech and artificial intelligence

where the emergence of what's said to be a low-cost AI Chinese chatbot has caused shockwaves.

Shares in Western tech giants fell sharply in value on Monday with the AI chipmaker,

Nvidia, one of the hardest hit.

Half a trillion dollars was wiped off its value after a Chinese startup, DeepSeek, stunned its American competitors

with the success of its AI app, reportedly made at a fraction of the cost of rivals like ChatGPT.

Despite only being launched this month, it's become the top-rated free application on Apple's App Store in the United States.

This is despite the US restricting the sale to China of the advanced chip technology that powers AI.

Stephanie here is a technology author and explains why this matters to all of us.

Right now, we've got really a competition between the two global superpowers, the United States and China,

from what is being arguably pitched as the battle for the technology of the

21st century. So it will matter for companies. It will matter for productivity. It will matter for

...