The head of Syria's main opposition alliance has said its international allies must honour what he said were pledges to supply heavy weapons.
Ahmed Jarba of the National Coalition told the BBC that he was promised them if Syrian government was at fault for the failure of recent peace talks.
The 11 core members of "The Friends of Syria" - including the US and UK - all blamed President Bashar al-Assad.
"Syrians are paying for time with blood," Mr Jarba warned.
In the interview with the BBC's Middle East editor Jeremy Bowen, he also blamed the Syrian government for the presence of Islamist extremists in the conflict, and promised to kick them out of Syria, as he claimed his forces had in several provinces already.
"Our main enemy is the regime that ruled this country for 50 years with fire and iron," he said. "When the revolution kicked off, there were no extremists or terrorists, there were [only] Syrian people looking only for their freedom."
While he admitted that the Assad government was the greater enemy he insisted that "regarding the terrorists, we fought and we will keep fighting against them... because we reject them and the Syrian people reject them as well."
In the interview, conducted at the National Coalition's headquarters in Istanbul, Mr Jarba also admitted he wished the US had gone through with its threat to bomb sites in Syria, saying that, if they had, "the conflict would have been much closer to the end".
"Assad has handed over the chemical weapons to save himself," he explained.
The time had come, Mr Jarba said, for diplomacy to take second place to changing the balance of power on Syria's battlefields in favour of his army, because only then would Assad feel he had to negotiate. "The Assad regime just knows the language of force," he said.
Mr Jarba's international backers may be less confident that is possible, says Jeremy Bowen, given the support the government in Damascus has from Iran and Russia, and the strength of jihadist insurgents who reject both the government and the secular opposition.
But without heavy, particularly anti-aircraft, weapons, Mr Jarba faces an uphill struggle to defeat President Assad, and that is a goal to which he is implacably committed, our correspondent adds.
"Syrians, after paying this price for freedom, won't allow this stupid man to rule them once again - whatever the price is," Mr Jarba said.