"We reiterated the devilish role that Iran is playing through hundreds of thousands of fighters on the Syrian soil", Hariri said in response to a question on what he had told Russian officials during their landmark meeting on Thursday.
The picture in Geneva is now open to a range of options, unless Russian Federation adopts a softer position, one that does not duplicate what the Syrian regime insists on implementing.
"It is counter-constructive", Gatilov told reporters.
In Moscow, a foreign ministry source confirmed that deputy Russian foreign minister Gennady Gatilov would meet opposition negotiators along with all sides in Geneva.
Hariri accused the government of using increased violence on the ground to foil talks in Geneva.
Russian Federation is struggling to salvage its bid to secure a deal to end six years of civil war in Syria as deepening differences with Iran risk a repeat of previous failed peace efforts led by the U.S.
However, de Mistura said he believes the issues of terrorism, ceasefire and delivery of humanitarian aid were the "specialty" of the "Astana" talks organized by Russia, Turkey and Iran, while the "Geneva" talks should rather focus on political matters.
While Western envoys were coordinating with the Syrian opposition in Geneva, the US envoy kept his head down and left after a few days to deal with other issues.
The strikes come as an opposition delegation gears up to meet Monday with United Nations mediator Staffan de Mistura in Geneva to continue talks aimed at resolving Syria's six-year-old war.
Resolution 2254 lays the basis for discussions on a political transition, including a new constitution, UN-supervised elections and accountable governance.
"The U.S.is not a direct participant in the UN-led talks", a spokesperson for the U.S. Mission in Geneva said.
Both sides agreed on the need that the issue of fighting terrorism be among the priorities of the agenda of talks aimed at solving the crisis in Syria.
"We met with (Syrian government negotiator Bashar) Ja'afari and he reconfirmed that he is not against the agenda proposal, but he said that terrorism should not be ignored and should also be on the agenda", Gatilov said.
Abu Mohammed al-Golani says in a video message posted Monday that Syrian opposition delegates in Switzerland "were handing victory" to a regime that is not victorious, referring to the government of President Bashar Assad.
In a mirror of the previous failed rounds of United Nations -led negotiations, the opposition is focusing on its demands for political transition, which it insists must include Assad's departure.
"Russia is in a very hard position, it's being torn between its traditional partners, Assad and Iran, and its potential partners in the fight against Islamic State - Turkey and the USA", said Alexander Shumilin, head of the Middle East Conflicts Center at the Institute for US and Canada Studies, a government-run research group in Moscow.