Damascus, Dec 12 (IANS): The Islamic State militant group has recaptured Syria's ancient city of Palmyra, just nine months after losing it to the government forces, a monitor group has reported.

Following four days of clashes with the Syrian army, the group on Sunday successfully recaptured the millennia-old oasis city of Palmyra in the eastern countryside of Homs province, Xinhua news agency quoted the Syrian Observatory for Human Rights as saying.

The city as well as its airbase, ancient part and citadel fell to the Islamic State, said the observatory.

Over 120 Syrian soldiers lost their lives during the offensive and tens of IS militants were also killed.

The Syrian army withdrew to the desert in southern Palmyra, amid intense Russian and Syrian airstrikes on the IS positions there, SANA news agency reported.

Meanwhile, Homs Governor Talal Barazi said the army had withdrawn from the city.

The IS started its offensive on Palmyra on Thursday, after bringing in around 4,000 fighters for retaking the city, SANA reported.

The Syrian army captured Palmyra on March 27 this year, after losing the city to the IS last year.

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

The city has an importance to the IS as it connects areas under the terror group's control in Deir al-Zour province with the central province of Homs.

The recapture of Palmyra is also important as the group's fighters in Iraq have started entering Syria recently after suffering great losses in battles against the Iraqi army and the US-anti-terror coalition.