Syrian troops entered the area near Palmyra Thursday under the cover of Russian airstrikes, fighting to regain the ancient city from Islamic State group militants, Reuters reported. Syrian state-run television and a monitoring group reported fighting on the outskirts of the city.

“We say to those gunmen, we are advancing to Palmyra, and to what’s beyond Palmyra, and God willing to Raqqa, the center of the Daesh gangs,” a Syrian soldier told state run media using another name for the Islamic State. The terror group, also known as ISIS, captured Palmyra in May 2015, giving the group a route to the eastern part of Syria. ISIS’ de facto capital is located in the city of Raqqa. 

The approximately 15,000 civilians who remained in Palmyra began fleeing the center of the city after ISIS advised them to leave over loud speakers, the Syrian Observatory for Human Rights reported based on information from its contacts on the ground. ISIS left mines around the outskirts of the city to slow the Syrian army’s advance, AFP reported. If Syrian troops succeed in capturing the city, it will mark a significant recovery of territory from ISIS.

The ancient city of Palmyra is known for its Unesco world heritage sites, including the Temple of Baalshamin and the Temple of Baal. Both structures were destroyed by ISIS after the group captured the city and SIS committed public beheadings in Palmyra’s ancient amphitheater. The United Nations has called ISIS’s destruction of cultural heritage sites and looting throughout Syria and Iraq a “war crime.” 

While fighting continued on the ground in Syria, Russian President Vladimir Putin met with U.S. Secretary of State John Kerry in Moscow to discuss the ongoing Syrian peace talks and the role of Kremlin ally Syrian President Bashar Assad. Putin withdrew a large part of Russia’s troops in Syria last week, arguing he had achieved his goals since directly entering the five-year-old conflict at the end of September.

“We both know that more needs to be done in terms of both the reduction of violence and the flow of humanitarian goods,” Kerry told Russian Foreign Minister Sergey Lavrov.

U.N. envoy Staffan de Mistura, who is charged with overseeing Syrian peace talks, met with delegations in Geneva Thursday stressing there needed to be a greater dialog among Syrian groups.