By Alexander Tanas

CHISINAU (Reuters) - Moldova's pro-Europe government fell on Tuesday when it lost a vote of no confidence that could affect the former Soviet republic's drive towards a place in the European mainstream.

The outcome, which left the ruling Alliance for European Integration badly damaged, places a question mark over whether a new government will continue the drive towards the European Union or seek closer relations with Russia.

After his government was defeated in a vote in which his erstwhile center-left coalition allies deserted him, Prime Minister Vlad Filat said: "This is a blow to Moldova and its citizens who dream of integration into the European Union."

"After the resignation of the government, it cannot be excluded that there will be changes to the direction the country takes," he said.

The three-party Alliance ousted the communists in 2009 and since then has worked to break with the Soviet past and integrate the tiny landlocked state, bordering Ukraine and EU-member Romania, into mainstream Europe.

Moldova is one of the poorest corners of Europe, with an average monthly salary of about $230. Heavily reliant on Russian energy supplies, its weak economy is kept afloat by cash remittances from several hundred thousands of Moldovans working in Russia and EU countries.

But the European Union views Moldova as a regional beacon of progress despite its poverty and has been signaling strongly that it is on track to sign landmark agreements on association and free trade at the end of this year.

Tuesday's vote, initiated by the opposition communists, parliament's biggest single faction, was the climax of weeks of feuding among the three main Alliance partners.

The communists seized the opportunity to call a no confidence vote after Filat, a 43-year-old businessman and head of the Liberal Democratic party, fell out publicly with other coalition leaders who called for his resignation.

These included Marian Lupu, leader of the center-left Democratic party who is speaker of parliament, and Mihai Ghimpu, a former acting president who heads the Liberal party.

SHOTGUN ALLIANCE

The Alliance has always been something of a shotgun 'menage a trois', with strains between the three partners frequently visible.

In January, Filat called for the resignation of Prosecutor General Valerii Zubco, an appointee of the Democrats, after a local pressure group accused Zubco of involvement in the death of a businessman on a hunting trip and a subsequent cover-up.

In an apparent tit-for-tat move, state prosecutors in turn launched abuse-of-office investigations against finance and health ministers - both of whom are appointees of Filat.

The simmering rivalries, personal feuds and conflicting business interests among the Alliance's leaders burst to the surface on February 13 when Filat accused his allies of corruption and withdrew his party's support for the founding coalition blueprint.

When it came to the vote on Tuesday, fifteen deputies from Lupu's party joined the communists in bringing Filat's government down.

The vote means that Filat's government must formally resign within three days, but will stay on as an interim one until agreement is reached on a new prime minister or - failing that - early elections are held.

With no real improvements to living standards and with the fragile economy weakened by falling European demand for Moldovan products such as wine, the communists remain strong in the countryside and may feel they can gain from a snap election.

Any return of the communists either by themselves or in a coalition would almost certainly change Moldova's strategic direction away from Europe towards Russia.

(Writing By Richard Balmforth; Editing by Robin Pomeroy)