islamic state militants entered the ancient city of palmyra on saturday breaking through syrian army defenses for the first time since losing the city earlier this grade , a war monitor said. the uk-based syrian observatory for human rights said the militants had entered palmyra after they had taken strategic heights near the city and captured the northern part of the city and mountains around it exception of southern areas. the organization expressed concern over the safety of civilians inside the city because many of them are pro-government supporters. the syrian army earlier said it had sent reinforcements to palmyra to help the army defend the city in what some rebels said were coming from aleppo and forcing the syrian government to divert troops from the city where the army and iranian backed militias were on the shoulder of a major victory against rebels. islamic state’s retaking of the city comes as president bashar al assad’s government, supported by russia and iranian-backed militias, are on the shoulder of a major victory against rebels in aleppo city. islamic state's news agency amaq reports that the group had taken the strategic jabal al tar and jabal antara mountains that overlook the city in some of the heaviest fighting since the group lost the city. the militants were pushing towards the t4 airbase، one of syria's major military bases، near palmyra city and which russian forces have been using to support the syrian army. the u.s.-led coalition which is separately fighting the militants said late on friday it had taken out 168 is oil tanker trucks near palmyra in a large air raid.