Russia, the only world power with close ties to the Syrian regime, urged President Bashar al-Assad on Friday to talk to the opposition as Moscow itself put out feelers to the rebels.
The new pressure on Assad came as Moscow revved up its bid to save a tattered peace process by first hosting a top Damascus envoy and then planning for a meeting Saturday with Syria peace mediator Lakhdar Brahimi.
Russia also invited the head of the opposition National Coalition for talks in either Moscow or a regional capital -- the Kremlin's first contact with a group formed in November and recognised by the West as the sole legitimate representative of Syrians.
But Moscow still views Assad as the legitimate leader, and its outreach to the regime's opponents found a cool response from the National Coalition chief.
Ahmed Moaz al-Khatib told Al Jazeera television that he would meet the Russians outside Moscow only on condition that they issued "a clear condemnation of the crimes committed by the Syrian regime."
The fast-paced but tricky diplomacy came as rebels pounded the Wadi Deif army base, one of the government's dwindling number of outposts in the northwest, the Syrian Observatory for Human Rights said.
Rebels on the ground said the jihadist Al-Nusra Front, blacklisted by Washington as a terror outfit, was leading the offensive.
Loss of the base would cut the main resupply route from the capital to second city Aleppo.
The Observatory said that at least 121 people were killed nationwide on Friday, 43 of them civilians.
Foreign Minister Sergei Lavrov said Russia still refused to back international calls on Assad to step down.
But he made explicit that Russia wanted Assad to put all options on the table after 21 months of violence that have claimed more than 45,000 lives.
"We actively encouraged... the Syrian leadership to maximally put into action its declared readiness for dialogue with the opposition," Lavrov told reporters when asked about his meeting on Thursday with Syrian Deputy Foreign Minister Faisal Muqdad.
He said Russia hoped to see Assad's government "underscore that they are open to discussing the widest range of items in line with the agreements reached in Geneva on June 30."
That accord -- rejected by the opposition and never implemented because of the fighting -- sought to quickly establish an interim coalition government but made no direct call on Assad to step down.
The West lacks direct access to Assad and needs Russia to convince him that his regime's days are numbered and that he cannot hang on to power through force alone.
In recent weeks, Moscow appears to have distanced itself from the rulers of what was its last big ally in the Middle East.
President Vladimir Putin has twice this month said that Moscow has no intention of propping up Assad, and Lavrov himself warned on Thursday that time was running out for Damascus to accept the terms of the Geneva accord.
"Russia has long realised that Assad has no future," said Carnegie Moscow Centre analyst Alexei Malashenko.
Moscow will be the focus of further diplomacy on Saturday when Russian officials hold talks with Brahimi.
The UN-Arab League envoy revealed on Thursday that he had been discussing the details of a transition government that had full powers and implemented "real change".
But Lavrov stressed that peace efforts were futile unless the West impressed on the armed opposition the need to engage in talks that left open the possibility of Assad staying on on an interim basis.
"I hope that the situation inside Syria will prompt reasonable members of the opposition to search for a way to start a political dialogue," he said.
Activists on the ground organised protests against Brahimi on Friday, however, accusing the envoy of "whitewashing the crimes of the murderer Assad."