Moscow - (AFP) - Russian President Vladimir Putin on Wednesday ordered the imposition of martial law in four Ukrainian regions: Donetsk, Luhansk, Kherson and Zaporizhia, which Moscow annexed in September.

Putin announced the measure during a televised meeting of the National Security Council. The Kremlin then issued a decree announcing the entry into force of martial law in these areas, as of midnight Thursday.

Putin's announcement came as Ukrainian forces made advances in areas controlled by Moscow for months.

"The Kiev regime refused to recognize the will of the people, rejected any proposals for negotiation. Shooting continues and civilians are dying," said the 70-year-old Russian leader.

He accused Ukraine of using "terrorist methods".

"They are sending sabotage groups to our lands," he said, saying that Moscow had thwarted other attacks after targeting the Crimean bridge, "including our nuclear energy facilities."

Under Russian law, martial law allows the army to build up, impose curfews and censorship, limit movements, and train foreign citizens.

"We are working on solving very complex and large-scale tasks to ensure security and protect the future of Russia," Putin added.