He has all the makings of a future film star. Good looks, a wide, winning smile. And bags of charm. Ibrahim, who is 12, lives in a dark, non-descript building that doubles as a rehabilitation centre for injured Syrians in the suburbs of the Jordanian capital, Amman.

He's been out rehearsing for a play and glides in to meet me, moving effortlessly on his crutches. A friendly hand stretches out to greet me and he flashes that smile.

He asks me if I'm brave enough to see his mangled leg - he nearly lost it in an airstrike that killed his mother, two sisters, three brothers, as well as his uncle and five of his cousins. He lists his dead relatives in such a matter-of-fact way, as if it's utterly normal to lose half of your family.

Ibrahim has just been given asylum, with his father, in Canada. He's due to leave in the next few days. "Great. You must be looking forward to it," I say.

"Not at all," he replies quickly. "It's too far away. Far too far." Ibrahim wants to go back to Syria as soon as he can. And he wants to be a war reporter. "The outside world doesn't know the half of what's going on there," he says.

Thousands of Syrian families are on the move in Europe, trying to escape from unimaginable horrors. But the children I meet in Jordan and in Lebanon almost unanimously just want to go home.

Rouaa's little brother - four months old at the time - was briefly in hospital. Their home now is a bleak, weather-worn camp on Mount Lebanon - her parents and five children in one small tent. Rouaa says she misses being able to cook their own food and share it.Rouaa, a delicate-featured friendly five-year-old, says she'd go back to Syria tomorrow if she could. She wants to find the doll she hid in a drawer as the family fled after the chemical attack on her neighbourhood in 2013.

In Jordan I'm introduced to a young boy who lost both legs, an eye and one of his hands in a landmine explosion. A word of warning - if you ever meet him, don't take him on at table football. He's ferocious. The grey plastic chair he's on rocks back and forth with the energy he's putting into his shots.

When I ask what he would change, if he could, about the past five years, he says simply that he wants to look forwards not backwards.

The following day he had prosthetic legs fitted. On his own in hospital - with no family members there to witness it - he took his first steps since the summer of 2014. He told the hospital staff helping him that he wanted to walk right out of the hospital. And he did, with huge determination. Step after hesitant step, he walked and he walked and he walked.

I meet another little boy, Mustafa, who also had to learn to walk again after a barrel bomb hit his family house on the outskirts of Aleppo. Both of his parents were killed and he spent a year in hospital.

He still needs a hip replacement. The hospital run by Medecins Sans Frontieres in Amman - which carries out reconstructive surgery on war victims - isn't at the moment equipped to do that. He's still partially paralysed because of shrapnel that can't be removed from his brain.

But at the tender age of five, Mustafa has already been an inspiration to others. When he arrived at the hospital, he couldn't stand, he was malnourished and so traumatised he couldn't eat. He'd scream whenever he saw anyone in a white coat. He left on his own two feet, a different boy.

And he left a big hole at the hospital. All the staff and many of the patients had fallen in love with him - his big brown eyes, his smile, his determination. I must admit that I did too.

I watch him in a nursery class, taking part in every activity and singing every song, showing a younger girl the moves. And he doesn't flinch - he even takes part - when the children sing a song about their mothers.

Imagine Mustafa's strength of character. Imagine too the psychological damage Syria's war has done to its children.

I came back home after five days away - the longest I've ever spent apart from my own two-year-old. I lay down beside him that night as he slept and held his hand. He has two hands. He is physically whole. We were warm and safe, and we were all together.

After five years of war, how many Syrian families have that?

Foreign Minister Walid Muallem, speaking in Damascus, ruled out any debate of presidential elections.

An opposition spokesman said the government's pre-conditions could halt the talks before they had even started.

US Secretary of State John Kerry is expected to meet his German, French, and British counterparts on Sunday.

Earlier, the US said violence had fallen dramatically since a cessation of hostilities began two weeks ago.

The main Syrian opposition umbrella group, the High Negotiations Committee (HNC), said on Friday it would push for an interim government with full executive powers in which President Bashar al-Assad and the current leadership would have no role.

The fate of President Assad has been one of the main stumbling blocks in previous rounds of tentative talks.

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UN special envoy to Syria Staffan de Mistura has said he wants to see presidential elections in the next 18 months, but on Saturday Mr Muallem dismissed the idea.

"Neither he nor anyone else has the right to talk about presidential elections. This is an exclusive right of the Syrian people,'' he said.

He described the opposition's demands for an interim government with full executive powers as a "red line".

"If this is what they [the opposition] think, I advise them not to come to the negotiations so that they don't make us tired and we don't make them tired," Mr Muallem said.

He said the Syrian government delegation would return to Damascus within 24 hours if the opposition did not turn up.

HNC spokesman Monzer Makhous accused Mr Muallem of "putting the nails in the coffin of Geneva".

"Muallem is stopping Geneva before it starts," he told Al Arabiya Al Hadath TV.

Syria's warring sides are under significant pressure from their respective backers to go to Geneva. No one wants to be blamed for any breakdown. So they are likely to keep their pledge to show up.

But there is an unwavering red line for Damascus - no discussion of President Assad's role, not even of presidential elections. Never mind that UN envoy Staffan de Mistura said elections would be discussed. Mr Muallem - and presidential adviser Bouthaina Shaaban in a BBC interview - say Mr de Mistura could not "dictate" the agenda.

The Syrian government has been emboldened by Russia's immense military support, as well its diplomatic weight which is shaping this new process. It is still not clear what Russia expects in Geneva. And the opposition, and its backers, have their own red line on President Assad's future.

Despite a truce that, unexpectedly, has largely held for two weeks, the gaps remain dangerously wide in these very early stages of a very fragile process.

The HNC has already said it will attend the UN-sponsored indirect talks in Geneva. The last round collapsed in February without agreement.

A temporary cessation of hostilities agreed by most participants in the conflict began at the end of last month. It excludes so-called Islamic State (IS) and al-Nusra Front, al-Qaeda's branch in Syria.

US Secretary of State John Kerry said on Saturday that US and Russian officials were meeting to discuss alleged breaches of the temporary truce by government forces.

But he said "perceived" violations of the cessation of hostilities should not derail the Geneva talks.

"The level of violence by all accounts has been reduced by 80-90%, which is very, very significant," he said.

"We believe that the start of talks this next week in Geneva presents a critical moment for bringing the political solution to the table that we've all been waiting for, even as we extend the humanitarian assistance and continue to try to reduce the violence."

The Syrian Observatory for Human Rights, a monitoring group, said air raids by the Syrian government had killed seven civilians in Aleppo on Friday. The claim cannot be independently verified.

More than 250,000 Syrians have been killed and millions more have been forced from their homes in five years of Syria's civil war that began with an uprising against Mr Assad.