Moldova's foreign ministry has expelled five Russian diplomats, ordering Moscow to remove them in a move that outraged the country's pro-Russian president.

The note about the decision was given to the Russian ambassador to Moldova Farit Mukhametshin on Monday afternoon, according to Artur Sarbu, Moldova's foreign ministry aide, who did not explain the reason behind the expulsion.

Mukhametshin confirmed that he received the note, but declined to elaborate.

The move comes amid tensions between the country's pro-Russian president and his West-leaning government.

It follows allegations that former Moldovan legislator Yury Bolbochan passed state secrets to the military attache of the Russian embassy, Alexander Grudin.

Bolbochan was arrested in March and charged with treason after a video was published of him meeting Grudin.

President condemns decision

The unnamed diplomats were given 72 hours to leave the country, according to Moldova's President Igor Dodon, who condemned the decision.

"The government has taken an outrageous act toward the Russian Embassy," he wrote on Facebook.

"I am deeply outraged of this unfriendly step by the representatives of the Moldovan diplomatic corps and I categorically condemn it.

"This was done most likely on orders from the West," he said. "This crude step will not be left without negative consequences."

Moldova has an East-West cultural, linguistic and political split, with Dodon, who was elected in November.

Dodon this year declared that he would be keen to cancel Moldova's EU association agreement and reestablish a relationship with Moscow, a move condemned by the country's pro-Western politicians.