FILE PHOTO Syrian army soldiers drive past the Arch of Triumph in the historic city of Palmyra, in Homs Governorate, Syria in this April 1, 2016 file photo. REUTERS/Omar Sanadiki/File Photo Image Credit: REUTERS

Beirut: Daesh militants seized the ancient Syrian town of Palmyra on Sunday from government troops despite a wave of Russian air strikes, a major advance after a year of setbacks in Syria and neighboring Iraq.

Backed by Russian air power, the Syrian government had recaptured Palmyra, home to towering 2,000-year-old ruins, to great fanfare in March. But the militants have been steadily advancing in recent days while the government has waged a major offensive against rebels in the northern city of Aleppo.

The Britain-based Syrian Observatory for Human Rights and the Palmyra Coordination group said Daesh militants fought their way into the town in a multi-pronged assault, forcing government forces to retreat to the south.

Russia had earlier claimed to have repelled the Daesh attack on Palmyra, saying it had launched 64 air strikes overnight that killed 300 militants. But hours later, the activists said Daesh had seized a castle just outside the town that overlooks its famed Roman-era ruins.

The militants killed around 50 members of Syrian government forces after launching simultaneous attacks on several regime positions near Palmyra on Thursday, the Britain-based Observatory said at the time.

They targeted areas including near the Mahr and Shaar oil and gas fields and seized government checkpoints, silos and the village of Jazal, northwest of Palmyra.

In May last year, the terrorist group seized several towns in Homs province, including Palmyra, where they caused extensive damage to many of its ancient sites.

The recapture of Palmyra was hailed as a major victory, with Russian celebrities travelling there since March staging concerts and making public appearances.