MOSCOW - Massive Russian air strikes have killed at least 30 militants in northwest Syria, where a Russian fighter jet was shot down, Russia's Defense Ministry said in a statement Saturday.

A series of high-precision weapon strikes has been delivered in the area controlled by the Jabhat al-Nusra terrorist group, which brought down the Russian Su-25 jet by using a portable anti-aircraft missile system in the Syrian province Idlib, said the statement.

"According to radio intercepts, more than 30 Jabhat al-Nusra militants were killed," said the statement.

Earlier Saturday, the ministry said a pilot survived the fighter jet crash but was later killed in a ground fight with terrorists.

"The pilot died in a fight with the terrorists," an earlier statement said.

"The Russian center for reconciliation of opposing sides in Syria and the Turkish side overseeing the Idlib de-escalation area are working to bring the Russian pilot's body home," it said.

The incident requires finding out which countries could have equipped the militants with the man-portable air defense system, Yury Shvytkin, the deputy chairman of the Russian lower house's defense committee, was quoted by Sputnik as saying.

In May 2017, the guarantors of the Syrian ceasefire, Russia, Iran and Turkey, agreed to set up the Syrian de-escalation zones in Syria, which includes Idlib province.

In December 2017, the Russian military announced that Syrian troops supported by Russian servicemen have completed the destruction of Islamic State terrorists in the war-torn country.

Later, Russian President Vladimir Putin announced the beginning of a partial withdrawal of Russian troops from Syria.

Russia reportedly spent an average of 156 million rubles ($2.6 million) every day in the past few years on military operations against terrorist groups in Syria.