CHISINAU (Reuters) - Russia joined Moldova's leftist opposition on Thursday in denouncing Romania's prime minister for remarks saying ex-Soviet Moldova's population was made up strictly of Romanians who spoke Romanian.

Romanian Prime Minister Marcel Ciolacu told a Romanian television interviewer this week: "There are no Moldovans, there is no Moldovan language. There are Romanians and the Romanian language."

Moldova, lying between Ukraine and EU member Romania, has at various times over the past 150 years been a part of the Russian empire, the Soviet Union and "Greater Romania".

Though its population includes ethnic Russians, Ukrainians and other groups and Russian is widely spoken, Romanian is the sole state language.

Parliament last year proclaimed the language to be Romanian rather than Moldovan, as it was known in Soviet times and for much of the period since independence from Soviet rule in 1991.

Russian Foreign Ministry spokeswoman Maria Zakharova, who regularly accuses Moldova's pro-European president Maia Sandu of encouraging Russophobia, denounced both Ciolacu's comments and the failure of Moldova's authorities to criticise them.

Romania, she said, was asking Moldovans to deny their own identity and language.

"What is striking is that such provocative statements by Romanian officials are blatant interference in Moldova's internal affairs and have gone without a proper response from Chisinayu," Zakharova told a briefing.

Moldova's Moscow-friendly opposition Socialist party said the comments were an "insult to our country and our citizens".

"But our questions are not to Mr. Ciolacu, but rather to Moldova's president, government and parliamentary majority for making no proper response to a boorish, chauvinistic statement."

Sandu, who has called a referendum later this year on joining the European Union, offered no comment.

The press secretary of her party of Action and Solidarity, which enjoys a majority in parliament, said Moldova was "a free country where all its citizens ...are respected and defended. We will all find ourselves in a common European space."

Sandu, who singles out Russia and corruption as the biggest threats to Moldova's sovereignty, is seeking re-election this year in a poll coinciding with the EU referendum.

(Reporting by Alexander Tanas, Editing by Ron Popeski and Lincoln Feast.)

By Alexander Tanas