Israeli Satellite Images Reveal new construction in Hmeimim Airbase, What's Russia doing?

New Israeli satellite images revealed this past week that some kind of construction and potential expansion is undergoing in the Russian Hmeimim Airbase North-west of Syria
According to Image Satellite International, the Russian project is not fully known yet; however, they believe it is likely the construction of new bunkers at the Hmeimim Airport ( Авиабаза Хмеймим )

Heavy construction at #Hmeimim Airfield, the #Russian base near Latakia, #Syria.#ISI #Russia #IMINT #VISINT #Airforce #Military #Defence pic.twitter.com/f9hnAl3hEr

— ImageSat Intl. (@ImageSatIntl) May 9, 2019

The Russian military took over the Hmeimim Airbase in late 2015. Since then, it has become their primary base inside of Syria.
Recently, the jihadist rebels  have repeatedly tried to attack the Hmeimim Airbase in retaliation for Russian’s bombardment of the southern part of the demilitarized zone.
The Russian Ministry of Defense maintains that all attacks by militants on the base failed to hit the Hmeimim Airbase.
Read more : Russian combat jet intercept U.S plane over Syria (Video)