Armenia's protest leader Nikol Pashinyan on Thursday ruled out any possibility of compromise with authorities, saying he should be elected prime minister in a vote next week.
Earlier in the day Armenia's parliament set May 1 as the date to elect a prime minister in a bid to defuse escalating tensions and Russian leader Vladimir Putin stressed the "importance" of the vote in phone talks with the acting head of government.
Observers have warned the crisis could destabilise the Moscow-allied nation which has been involved in a decades-long territorial dispute with Azerbaijan.
Addressing supporters at a rally in the capital Yerevan, Pashinyan said he was the only suitable candidate for prime minister and rejected the possibility of any backroom deals with the ruling Republican Party.
"If I am not elected prime minister, then Armenia will not have a prime minister at all," said the 42-year-old former newspaper editor.
"Get me right -- the issue is not about getting me elected prime minister, it's about getting rid of the corrupt system."
After electing a prime minister Armenia is expected to hold new parliamentary elections.
The opposition accuses the ruling party -- which controls a majority in parliament -- of being unwilling to cede power after the country's leader Serzh Sarkisian quit his new post of prime minister earlier this week after days of protests.
The Yelk opposition bloc nominated Pashinyan for prime minister, but he was 13 votes short of a majority on Wednesday. A candidate would need 53 votes to get elected.
Pashinyan called a temporary halt to protests across the country and said he was willing to hold talks with acting head of government Karen Karapetyan on Friday in front of journalists.
An attempt to hold such negotiations earlier in the week collapsed.
Russia - which has a military base in Armenia -- has pledged it would not intervene but its top officials welcomed counterparts from the South Caucasus nation for talks on Thursday and Putin discussed the crisis with Karapetyan.
"It was stressed that the settlement of the crisis situation in Armenia should be conducted solely within the legal framework," the Kremlin said after the phone talks.
Speaking earlier in the day, Putin's spokesman Dmitry Peskov urged the importance of "compromise."
In Moscow, Russian Foreign Minister Sergei Lavrov met with his Armenian counterpart Eduard Nalbandyan while Kremlin officials also held talks with the country's acting Vice Premier Armen Gevorkyan.
Foreign ministry spokeswoman Maria Zakharova said the top diplomats from Russia and Armenia discussed the situation around Nagorny Karabakh, a breakaway statelet with an Armenian ethnic majority that is internationally recognised as part of Azerbaijan.
Officials from the Russian embassy in Yerevan have also met with Pashinyan.
The country's leader Serzh Sarkisian stood down Monday from his new post of prime minister after days of largely peaceful protests in the impoverished country of 2.9 million people.
The opposition had accused 63-year-old Sarkisian of wanting to extend his grip on power after serving a decade as president, saying he failed to tackle a litany of problems including poverty, corruption and the influence of tycoons close to power.
Analysts said the situation in Armenia was hugely unpredictable.
"It's impossible to tell if the country will come out of this chaos on May 1," analyst Ervand Bozoyan said, adding that frantic backdoor negotiations were under way among political parties.
Analyst Stepan Safaryan said that, while the core of the Republican Party has no intention of backing down, he did not rule out that some of the party's lawmakers would vote for Pashinyan.
Protesters said Thursday it was time for the Republican Party to give way to new political forces and warned of the risk of clashes.
"Everything has been peaceful so far, but there still is a risk of turmoil, even violence," said Iren Vakhtangyan, a 28-year-old historian.
Hayk Gevorkyan, a 58-year-old economist, said the old elites cannot stay in power any longer.
"They must go! There is no time for political manipulations and power struggle," he told AFP.
"We also fear that Pashinyan could make a deal with oligarchs. If he disappoints the people, we will get rid of him just as we got rid of Serzh."
Armenian opposition supporters demonstrate in downtown Yerevan