The governing party in Armenia thwarted the opposition leader’s effort to become prime minister on Tuesday, setting the stage for continued upheaval as street protesters ratchet up their efforts to force the ruling elite to loosen its grip on the country.

In an extraordinary session of Parliament, the opposition leader, Nikol Pashinyan, urged the Republican Party, which has the most lawmakers, to install him as prime minister, warning that if they did not, they would face a “political tsunami” on the streets.

When all but one member of the party voted against him anyway, Mr. Pashinyan called for a national strike starting Wednesday to paralyze roads, railroads, airports, schools and public services.

“In the Armenian Republic there is no power that can stand against you,” he told a cheering crowd of tens of thousands of supporters gathered on Republic Square in central Yerevan, the capital, where many had spent more than eight hours watching live broadcasts of the speeches in Parliament.