BUCHAREST, ROMANIA -- Romania's defence minister Vasile Dincu resigned Monday, citing difficulties working with the country's president who's also chief of the NATO country's armed forces.

Dincu's resignation comes a week after sparking controversy by suggesting that Ukraine's only chance for peace would be in negotiating with Russia, in contrast to Romania's official stance.

Dincu, a member of the ruling Social Democrat party (PSD) who has held the post in the coalition government for almost a year, said on Facebook that he sent his resignation letter to Prime Minister Nicolae Ciuca.

Romania, a European Union and NATO member that borders war-torn Ukraine, has become an increasingly important western ally since Russia invaded Ukraine on 24. Feb, and hosts multinational battlegroups and air defence systems for the 30-nation security alliance.

Dincu explained his decision to resign as necessary to avoid hindering decision-making in military programs and "to not block a number of projects absolutely necessary for the optimal function" in the defence ministry and army.

No interim minister or successor has yet been announced.

Marcel Ciolacu, the leader of PSD, said Monday that he has requested incumbent Prime Minister Ciuca, a former defence minister, to step in as interim "because Romania is obliged to ensure stability on the eastern flank of NATO."