We start in the Middle East, the presidents of Iran, Russia and Turkey are set to make a last diplomatic effort today in Tehran to decide the future of Idlib province - Syria's last major rebel bastion. Both Moscow and Tehran confirmed their support for the government forces, vowing to wipe out 'terrorists'. However, there are fears of a humanitarian disaster in Idlib, as hundreds of civilians fled the northwestern province on Thursday. The Tehran meeting could determine the scale and timeline of an Idlib offensive, which the United Nations has warned may displace 800-thousand people. Our correspondent Dan Ashby has the story.

There have been many dark days for Syria, but the Battle of Idlib could bring the bloodiest of them all. Russia and the Syrian Government are preparing to flush out thousands of what they say are terrorists, But more than a million children are trapped, and the US has warned it will not tolerate wholesale slaughter.

DONALD TRUMP US PRESIDENT "And I just tell you that they will hopefully be very, very judicious and careful, because the world is watching. There cannot be a slaughter. If it's a slaughter, the world is going to get very, very angry and the United States is going to get very angry too. OK?"

But Russia has brushed aside US warnings of air strikes, and says the problem of Idlib must be solved.

DAN ASHBY MOSCOW "Moscow has described Idlib as a 'festering abscess' and a 'hotbed of terrorists'. Already its war planes are bombing targets and it is all set to back the Syrian Government in what's likely to be the final bloody battle of this war."

But in last-minute talks, Russia, Iran and Turkey will try to find a humanitarian solution, that would see families move into Syrian Government control. The fear is that many will not trust Bashar Al-Assad's assurances, and will stay in the firing line.

RUSSIAN MILITARY EXPERT "Why doesn't the US like our peace talks? Russia, Turkey and Iran took responsibility to arrange the Syrian complex settlement without US participation. the US doesn't like the Turkey, a Nato country, leaning towards Russian and Iran. So the Americans are trying to undermine our peace settlement at any cost."

Iran says it will continue to back the Syrian Government, and yet Turkey fears a massacre may happen. Once again, there are five governments wrangling over what should happen next. And three million people whose fate depends on it.