(Reuters) - Moldova's Moscow-backed separatist region of Transdniestria extended its state of emergency on Friday for another month as it grapples with an energy crisis after losing access to Russian gas supplies that had propped up its economy for decades.

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 pro-Russian separatist enclave, authorities said on Monday, as Moldova and Russia traded blame for an escalating energy crisis.