Moldovan Prime Minister Vlad Filat's pro-Europe government resigned on Friday after being defeated in a confidence vote, raising the prospect of early elections unless a new government is approved within six weeks.
Filat's government effectively collapsed on March 5 when it lost a confidence vote in which it was deserted by two coalition parties in the ruling Alliance for European Integration.
The Alliance, which has run the former Soviet republic since it pushed the communists into opposition in 2009, has been split for months by internal feuding and personal rivalries.
Political leaders say Moldova's course toward European integration could be threatened if the three main Alliance partners do not settle their differences and end the crisis.
The signing of landmark association and free trade agreements with the European Union at the end of the year could, particularly, be in jeopardy, they say.
Moldova is one of Europe's poorest countries with an average monthly salary of about $230. Heavily reliant on Russian energy supplies, its economy is kept afloat by remittances from several hundred thousand Moldovans working in Russia and EU countries.
The three-party Alliance has worked to break with the Soviet past and map out a route to mainstream Europe for the tiny landlocked state of 3.6 million people, which lies between Ukraine and EU-member Romania.
Despite Moldova's poverty and political uncertainty, the EU has welcomed Chisinau's reforms and has signaled it is on track to sign key agreements in November.
President Nicolae Timofti, who accepted Filat's resignation on Friday, now has 45 days in which to secure parliamentary support for his nominee for prime minister.
If he fails to do so within this time frame, early elections must be called. Commentators say this outcome might result in a comeback by the communists, who remain strong particularly in the countryside, and could tilt policy back towards Russia.
Mutual recrimination has been strong between Filat, a 43-year-old businessman who heads the Liberal Democratic party, and two other Alliance leaders, parliament speaker Marian Lupu and former acting President Mihai Ghimpu.
But with early elections likely to bring the communists back into power, commentators do not rule out Timofti finally securing support again for Filat to return as prime minister.
Under the constitution, Filat and his ministers will continue in a caretaker role until a new government is formed.