There were 26 passengers and 6 crew, the ministry said in a statement carried by RIA Novosti agency. It did not specify whether all of them were in the military.

"The reason for the crash according to preliminary information could have been a technical fault," the ministry said, adding that the plane had not come under fire according to a report from the ground.

The transporter was around 500 metres (yards) from the runway, the statement said.

A commission will investigate the causes of the crash.

The Russian military prosecutor's office has initiated a check of possible violation of aviation safety, a spokesman said.

Antonov-26 planes are used by the military in Syria for internal flights transporting troops and supplies between provinces, Kommersant business daily reported.

The planes have also been used on press tours.

Moscow began conducting air strikes in Syria in September 2015, and its intervention has swung the nearly seven-year conflict firmly in favour of the forces of ally President Bashar al-Assad.

Russia's President Vladimir Putin made a surprise visit to Hmeimim in December where he ordered the start of a pullout of Russian troops, saying their task in the war-torn country had been largely completed.

Three battalions of military police and officers of the Russian Centre for Reconciliation would remain in Syria, as well as two Russian bases, Defence Minister Sergei Shoigu said on a subsequent trip.

- Military losses -

Russia's official military losses in the Syrian war before the crash were 45. If all those killed Tuesday were serving in the military, the toll would rise to 77.

The most recent officially acknowledged military loss in battle in Syria was last month when a Russian pilot was killed after his plane was downed over Idlib province.

Russia has also acknowledged that five of its citizens were killed in a US-led coalition bombing in the eastern Deir Ezzor province on February 7, in the first admission of non-military combat casualties.

Moscow also said "several dozen" were wounded in the coalition strike.

The United States said its strike killed at least 100 regime and allied fighters and various reports indicated a death toll of up to several hundred Russians from the strike.

Russian nationals are regularly reported to be serving as paid mercenaries in Syria and taking on dangerous missions that often lead to casualties.

However, officials deny this and serving as a mercenary is illegal under Russian law.

Hmeimim base has been targeted in several attacks.

The military said that two drones carrying explosives attacked the base in January without causing any casualties.

On New Year's Eve last year, a mortar attack on the base killed two Russian soldiers.

In the most recent accident at the base, a Sukhoi military jet crashed while trying to take off in October, killing two crew.