A Russian helicopter crashed in Syria on New Year's Eve killing both pilots following a technical fault, Moscow's defence ministry said Wednesday.

The Mi-24 military helicopter was flying to Hama, northwestern Syria, and there was no firing from the ground, agencies quote the ministry as saying.

"Both pilots died in a hard landing 15 km (nine miles) from the air base," the ministry said, adding that a technician had been injured and taken to another air base at for emergency treatment.

The investigative blog Conflict Intelligence Team (CIT) quoted a post from Forumavia aviation forum saying the helicopter had tripped over power line wires and crashed while escorting a convoy.

The post did not specify whether the helicopter was escorting a humanitarian convoy or combat unit and the defence ministry did not give any further details.

Russia became involved in the multi-front conflict in September 2015, when it began an aerial campaign in support of President Bashar al-Assad's military.

Russia's Defence Minister Sergei Shoigu last month said the military had completed the partial withdrawal from Syria ordered by President Vladimir Putin, but Russia will maintain a presence in the country, including three battalions and two bases.

Moscow acknowledged in recent months that its special forces are also active on the ground in the offensive against Islamic State jihadists.