BAKHMUT, Dec 9 (AFP) - Russian forces shelled the entire front line of Donetsk region in eastern Ukraine on Thursday, Ukrainian officials said, part of what appeared to be the Kremlin's scaled-back ambition to secure only the bulk of lands it has claimed.

The fiercest fighting was near the towns of Bakhmut and Avdiivka, the region's governor Pavlo Kyrylenko said in a TV interview. Artillery slammed into the town of Toretsk southwest of Bakhmut, killing one civilian and damaging 12 buildings, Kyrylenko said.

He said "the entire front line is being shelled" and Russian troops were also trying to advance near Lyman, which was recaptured by Ukrainian forces in November, one of a number of setbacks suffered by Russia since invading its neighbour in February.

In Bakhmut and other parts of the Donetsk region that neighbours Luhansk province, Ukrainian forces countered with barrages from rocket launchers, Reuters witnessed.

Ukraine's military command said Russian artillery attacked civilian infrastructure in the towns of Kupiansk and Zolochiv in the northeastern region of Kharkiv, and Ochakiv in the Mykolaiv region. Ukrainian anti-aircraft units downed several of the missiles trained on Kharkiv region on Thursday evening, governor Oleh Synehubov said on the Telegram messaging app.