Syrian President Bashar al-Assad has said that Russia has been supplying weapons to Damascus under contracts signed since the conflict in the country began in 2011, as well as under earlier deals.

Assad's comments, made in an interview published by Russian government newspaper Rossiyskaya Gazeta on Monday, appeared to contradict Moscow's claim that any arms supplies to the Syrian government were agreed before the conflict began.

"There are contracts that had been sealed before the crisis started and were carried out during the crisis. There are other agreements on arms supplies and cooperation that were signed during the crisis and are being carried out now," Assad said.

"They went through some changes to take into account the type of fighting the Syrian army carries out against the terrorists," he said in the full text of the interviews, excerpts of which were published last week.

Assad gave no details of the weapons being supplied by Russia, the world's second-biggest arms exporter, since the start of the conflict which has killed more than 220,000 people and displaced millions.

Kremlin spokesman Dmitry Peskov did not confirm Assad's statements, but defended Moscow's military ties with Damascus, a long-standing ally.

"In fact, Moscow has always highlighted that there have been and are no embargoes on military cooperation. There are no legal limitations on us," he told reporters.

Russia's Defence Ministry, contacted by telephone by the Reuters news agency, declined immediate comment.

Russia and Iran have reportedly continued to provide much of the military support to the Syrian government, despite war crimes, crimes against humanity, and other atrocities allegedly committed in its bid to crush the country's four-year uprising.

Source: Agencies