The United States and France warned the Syrian regime today against trying to disrupt the fragile ceasefire as the warring sides prepared for fresh peace talks to end the brutal conflict.
With the five-year anniversary of the violence looming, the main players in the Syrian conflict were tomorrow to resume UN-brokered indirect negotiations in Geneva in the latest bid to end bloodshed which has killed more than 270,000 people.
After meeting with European allies in Paris, US Secretary of State John Kerry hit out at comments by his Syrian counterpart who said talk of removing President Bashar al-Assad would be a "red line" in the negotiations.
French Foreign Minister Jean-Marc Ayrault went further, describing Walid Muallem's comments as a "provocation" and a "bad sign" for the attempts to find peace.
Kerry warned Damascus and its allies Russia and Iran against "testing boundaries" or lessening their compliance with a fragile February 27 truce that has largely held despite the sides trading mutual accusations of violations.
While analysts say much has changed since the last round of talks collapsed in February, the fate of Assad and the holding of elections with 18 months remain huge obstacles.
Speaking in Damascus on today, Muallem said: "We will not talk with anyone who wants to discuss the presidency... Bashar al-Assad is a red line."
Kerry said the Syrian minister was "clearly trying to disrupt the process... Clearly trying to send a message of deterrence to others.
"But the fact is (Assad's) strongest sponsors Russia and Iran have both adopted... An approach which dictates that there must be a political transition and that we must have a presidential election at some time," he added.
Kerry urged Russian President Vladimir Putin to bring the Syrian regime into line, saying he should be concerned that Assad had used his foreign minister "to try and act as a spoiler, to take off the table something that president Putin and Iran had committed to".
"So this is a moment of truth, a moment where all of us have to be responsible."
Kerry hailed the fact that the ceasefire had led to a reduction of violence of up to 90 per cent, and made possible the delivery of emergency supplies to some 150,000 civilians in besieged areas.
He said the coalition had pushed the Islamic State group out of 20 per cent of the territory it held in Syria and that 600 IS fighters had been killed in the last three weeks.
