Parts of the ancient city of Palmyra were reduced to rubble by the jihadists
Fighters with the Islamic State group (IS) have seized more territory close to the ancient Syrian city of Palmyra, a monitoring group says.
IS held Palmyra and its nearby ruins for 10 months before it was recaptured by Syrian government forces in March.
But the group launched an offensive earlier this week, and has captured land on several fronts.
The UK-based Syrian Observatory for Human Rights said IS had killed 49 Syrian troops near Palmyra on Friday.
Meanwhile, the US-led coalition fighting IS says it has destroyed 168 oil tankers, external belonging to the group near Palmyra, in the largest raid of its kind so far. The assault on Thursday led to some $2m (£1.6m) of losses to the group.
The Syrian Observatory said, external there had been heavy fighting on Friday on the outskirts of the city, and that IS had succeeded in seizing several areas. Reinforcements from the Syrian army were expected, it added.
The Islamic State group's news agency Amaq posted footage that appeared to show government soldiers fleeing their positions west of Palmyra, Reuters news agency reported.
It said the fighting was some of the heaviest in the area since IS militants were pushed out nine months ago.
IS 'loses 50,000 fighters in two years'
Why IS militants destroy ancient sites
IS destroyed a number of monuments during its 10-month occupation of the Unesco World Heritage site and the adjacent city of Tadmur.
Two 2,000-year-old temples, an arch and funerary towers were left in ruins.
The jihadist group, which has also demolished several pre-Islamic sites in neighbouring Iraq, believes that such structures are idolatrous.
While some treasured monuments were destroyed, much of the historic site was left undamaged. The city was later reclaimed with the support of air strikes by the Russian air force.
IS has since lost large amounts of territory across Syria and Iraq.
