Damascus, March 27 (IANS): More than 400 Islamic State (IS) militants were killed in recent battles in Syria's ancient city of Palmyra, a monitor group reported on Sunday, as the Syrian army fully captured the millennia-old oasis city.

During the three-week-long military campaign backed by Russian and Shia fighters, the Syrian army has killed more than 400 IS militants, and lost 180 of its soldiers, Xinhua news agency cited Syrian Observatory for Human Rights as saying.

Meanwhile, the national Syrian TV said that the Syrian army has fully recaptured the ancient city of Palmyra, which was controlled by the IS militants since last May.

The Syrian army and its allied fighters destroyed the last position of the IS in Palmyra, and started combing the city to dismantle explosive devices, said the report.

Meanwhile, a military source said that the IS withdrew from the city under the heavy attacks and shelling by the Syrian army.

The source, who spoke on the condition of anonymity, said the IS militants pulled out toward the town of Sukhneh, east of the central province of Homs.

Since capturing it last May, the IS group destroyed the city's military prison as well as several Islamic tombs and archaeological sites.

The IS also put on public executions of soldiers and people accused of working for the government.

Palmyra contains the monumental ruins of a great city that was one of the most important cultural centres of the ancient world.

Syria has many prehistoric, Greek, Byzantine and Islamic heritages. Before the crisis, Syria had attracted many multinational archaeological missions coming to search for new clues of historical facts on the development of civilisations.