Chris Barrow

I'm Chris Barrow, and at 4GMT, these are our main stories.

A picture of violence and horror is emerging in Iran as anti-government protests continue across the country.

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Large crowds have returned to the streets of Iran's capital, Tehran, as anti-government protests spread across the country, despite increasingly severe warnings from the authorities.

Witnesses say families, including children, are taking part.

In his latest comments, President Trump has said Washington, in his words, stood ready to help.

So what could a US intervention look like?

David Petraeus is a former CIA director.

For an update on the latest situation on the ground in Iran, I spoke to our US-based BBC Persian correspondent, Bahman Kalbasi.

And a warning, you may find some of what he shared distressing.

And they are persisting despite an internet blackout, getting information out being extremely difficult.

I guess these are some of the tactics of the authorities to try and suppress these protesters.

There have been calls from the exiled Prince Reza Pahlavi for people to keep coming out, for Iranians to keep protesting.

Are his calls particularly powerful?

Is that driving a lot of the protesters or does he not have as much support as perhaps people might think?

Bahman Kilbassy.

And you can hear and see more on the protests in Iran on our YouTube page, where we ask our chief international correspondent Lise Doucette whether this could be the end of the religious regime.