IS gain ground in oil-rich Syria province

200,000 people live in Deir Ezzor city, besieged by IS since early 2015

DEIR EZZOR - The Islamic State group gained ground around a key eastern Syrian city on Sunday, a monitor said, despite a heavy air strikes by government warplanes.
The jihadists pressed their brutal assault on Deir Ezzor for the second day, seizing territory near an air base on the city's edges, according to the Syrian Observatory for Human Rights.
"IS seized several hilltops that overlook the airport," and clashes gripped the area on Sunday, said Observatory head Rami Abdel Rahman.
The advance came "despite more than 120 air strikes carried out by regime forces on jihadist positions since Saturday morning, in addition to heavy artillery fire," he said.
Around 200,000 people live in Deir Ezzor city, which has been besieged by IS since early 2015 and is the capital of the oil-rich province of the same name.
IS already controls more than half the city, but it has sought to capture the remaining government-held territory, including the military airport.
It launched one of its fiercest assaults yet on Saturday, unleashing a wave of tunnel bombs and suicide attackers.
At least 12 government fighters and 20 IS jihadists were killed.
A military source in Deir Ezzor said that IS was "amassing its forces to attack Deir Ezzor and breach government lines" in order to cut off regime access to the base.
The extremist Sunni Muslim group has lost swathes of territory in northern Syria to Kurdish fighters as well as a Turkish-backed rebel alliance, but it remains on the offensive in other parts of the country.
In addition to its push in Deir Ezzor, IS recently recaptured Palmyra in central Syria from government forces.
The jihadist faction is excluded from a nationwide ceasefire in Syria, in place since December 30 but increasingly strained by fighting.
The truce is meant to pave the way for peace talks later this month in the Kazakh capital Astana.