(Reuters) - Russia has ordered its warplanes in Syria to fly higher to avoid being shot down by shoulder-launched anti-aircraft missiles after one of its jets was shot out of the sky at the weekend, the Izvestia daily reported on Monday.

Syrian rebels downed the Russian SU-25 plane on Saturday in Idlib Province. The defense ministry said the pilot ejected, fought with rebels on the ground, then blew himself up with a grenade when they got close to him.

Izvestia, citing the Russian Defense Ministry, said a decision had been taken that such planes would in future only fly above 5,000 meters (16,400 ft) to keep them safe.

It said that such a policy had previously been in force, but that the SU-25s had for some reason started flying at lower altitudes in recent days.

The Kremlin said that shoulder-launched missiles obtained by rebels now posed a threat to all planes operating in Syria, but that it was too early to say who had supplied the weapons system used to shoot down the Russian SU-25.

"It's extremely worrying that shoulder-launched surface-to air missiles are in the hands of the terrorists," Kremlin spokesman Dmitry Peskov told reporters on a conference call.

"It's a huge danger for all governments."

Russian media have reported that Syrian and possibly Russian special forces are operating in the area where he was killed to try to retrieve his body, along with fragments of the projectile that struck his plane, to try to work out who supplied it to the rebels.

Peskov did not signal wider changes in Russia's policy in Syria where Moscow has been supporting President Bashar al-Assad's army for more than two years.

He said that Russia had enough firepower left in Syria to deliver "crushing blows" to rebel forces as and when needed.