The head of Moldova’s breakaway region Transnistria has urged residents to burn firewood for heating and warned that blackouts cannot be avoided, after Moscow stopped supplying gas via Ukraine.

More than 51,000 households were left without gas and 1,500 apartment buildings had no winter heat in Moldova's Moscow-backed separatist enclave, authorities said on Monday, as Moldova and Russia traded blame for an escalating energy crisis.

Moscow breakaway region of Transnistria halted almost all industrial activity except for food production, following the end of Russian gas flows through Ukraine, Interfax reported.