By Alexander Tanas
CHISINAU (Reuters) - A minister in Moldova's pro-European government and two of his deputies resigned on Monday, after their party withdrew from the ruling coalition over the arrest of its deputy chairman on corruption charges.
While the now two-party coalition retains a de facto majority in the 101-seat parliament, the Liberal Party's exit threatens more instability in the ex-Soviet nation, which has seen three governments fall since 2015.
On Friday, the Liberals quit the coalition in protest at the arrest of Chisinau mayor and Liberal deputy chairman, Dorin Chirtoaca, for alleged abuse of office linked to the distribution of parking contracts in the capital.
Monday's resignation by Environment Minister Valeriu Munteanu is expected to be followed by the departure from the cabinet of Education Minister Corina Fusu and Gheorghe Brega, a deputy prime minister.
Chirtoaca's defenders say his arrest is politically motivated rather than a result of the authorities' desire to crack down on endemic graft.
"This isn't a fight with corruption, but with the Liberal Party," Liberal Party leader Mihai Ghimpu told reporters on Friday.
Moldova ranks 123 out of 176 countries on Transparency International's Corruption Perceptions Index and the disappearance of $1 billion from the banking system nearly bankrupted the country, Europe's poorest, in 2015.
Ghimpu said Moscow-backed President Igor Dodon was responsible for orchestrating a campaign against the Liberals, who favor unification with European Union member Romania.
"I think Dodon will sign their (the ministers') resignation decrees with pleasure," he said.
Dodon won the presidential race in late 2016, reflecting a loss of trust in pro-European leaders in the wake of the billion-dollar banking scandal.
Mayor Chirtoaca, who is under house arrest, was one of seven officials and businessmen detained over the past three weeks in connection with the parking graft investigation. He could not be reached for comment.
(Writing by Alessandra Prentice; Editing by Toby Chopra)