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

I'm Valerie Sanderson, and in the early hours of Saturday the 22nd of March, these are our main stories.

Riot police in Turkey have clashed with demonstrators as tens of thousands come onto the streets of main cities in the country

to protest against the detention of the popular mayor of Istanbul.

Heathrow Airport is beginning to get back to normal

after a fire at a nearby electricity substation

shut down Europe's busiest hub causing chaos.

A hearing is taking place in the US

to decide on the legality of the deportation of alleged Venezuelan gang members.

Also in this podcast.

I think if America doesn't help Ukraine, that a ceasefire will be agreed soon, but on extremely unfavourable terms for Ukraine.

As negotiations to end the fighting in Ukraine continue,

we hear from troops in the region of Sumi, close to the Russian border in the northeast.

For three consecutive nights, thousands of protesters have flooded the streets of Istanbul and other cities

over the arrest of Turkish President Erdogan's main rival, Ekram Imamulu.

On Friday night, there have been scenes of violence.

The area around Istanbul City Hall was brought to a standstill,

with riot police deploying tear gas near to where Mayor Imammolu is due to stand trial on charges of bribery.

Addressing the protesters, Turkish opposition leader Osgar Ozil called for his release.

Democrats are not afraid of the square.

Democrats are brave, respectful of protest and understanding.

But dictators are afraid of squares.

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