After Saudis say their decision to deploy troops in Syria is 'final,' Medvedev issues a dire warning.

Russian Prime Minister Dmitry Medvedev warned Thursday that if Arab forces entered the Syrian war, they could spark a "new world war" and urged ceasefire talks instead.

Asked about proposals by some Arab countries to enter the conflict under a US command, Medvedev said, "that would be bad because ground offensives usually lead to wars becoming permanent."

"The Americans and our Arabic partners must think hard about this: do they want a permanent war?" he was quoted as telling the German Handelsblatt business daily.

"Do they really think they would win such a war very quickly? That's impossible, especially in the Arabic world. There everyone is fighting against everyone...everything is far more complicated. It could take years or decades."

"Why is that necessary?" he added, according to a pre-released excerpt from the daily's Friday edition. "All sides must be forced to the negotiating table instead of sparking a new world war."

Medvedev's comments come after Brig. Gen. Ahmed Al-Assiri, the spokesman of the Saudi-led coalition force in Yemen, announced Thursday that Saudi Arabia's decision to send troops to Syria is "final."

He said that Riyadh is “ready” and will fight with its US-led coalition allies to defeat Islamic State (ISIS) in Syria, adding that the decision on whether to utilize the deployment will be up to Washington.

Russia along with Saudi Arabia's fierce Shi'ite rival Iran have been militarily propping up Bashar al-Assad's regime in Syria.

Al-Assiri on Thursday also said that the Islamic Military Alliance will come into being in two months' time.

Thirty-five Muslim countries released a joint statement announcing the formation of the alliance against terrorism in December of 2015. The alliance’s joint command center is located in the Saudi capital - Iran is not among the countries taking part.

Medvedev's warnings regarding Syria come the same Thursday that US Defense Secretary Ashton Carter revealed NATO is also considering joining the US-led coalition against ISIS in Syria.

AFP contributed to this report.