Four Russian military personnel were killed and two injured when their vehicle was targeted with explosives in central Syria last week, a defence ministry statement quoted by Russian agencies said Monday.

"Four Russian servicemen died when their car exploded on a radio-controlled IED on February 16, 2017, in Syria," the statement said.

"Two more were injured. Russian military medics are trying to save their lives."

"The convoy of Syrian army cars, in which the vehicle with Russian military advisers was travelling, was en route from the Tiyas airfield area toward the city of Homs," it said.

"After they travelled four kilometres, a radio-controlled explosive was activated under the car with Russian servicemen."

The four deaths raise the number of Russian military officially reported killed in Syria to 26 since it started its campaign in Syria in support of President Bashar al-Assad on September 30, 2015. Another soldier committed suicide.