Apparently the Kurds have struck a deal with Assad's government.
The Kurdish-led administration in northern Syria said the Syrian army would deploy along the entire length of the border as part of the agreement.
This deployment would assist the SDF in countering "this aggression and liberating the areas that the Turkish army and mercenaries had entered", it said in a statement.
The move also "paves the way to liberate the rest of the Syrian cities occupied by the Turkish army such as Afrin", it added.
The deal represents a significant shift in alliances for the Kurds, after losing the military protection of their long-term US partners in the area.
I think the Syrian army is no match for Turkey without the Russian airforce (and navy) though.
Russia has implicitly condemned Turkey's invasion, but in rather non-specific terms. On Oct 12, Putin said:
“Everyone who is illegitimately on the territory of any state, in this case Syria, must leave this territory. This applies to all states,” Putin told state news agencies RT, Sky News Arabia and Al Arabiya in an interview, according to Reuters.
On Oct 15, the Russian position seems to have hardened a bit:
Russia called Turkey’s military incursion into northeast Syria “unacceptable” and said on Tuesday the operation had to be limited in time and scale, a rare broadside that suggests Moscow’s patience with Ankara is wearing thin. [...]
“We didn’t agree with the Turks any questions about their presence in Syria and we don’t approve of their actions,” envoy Alexander Lavrentiev told reporters in Abu Dhabi during an official visit there by Putin.
He said Turkish troops had the right under an agreement struck between Damascus and Ankara in 1998, the Adana pact, to temporarily push up to a maximum of 10 km (6 miles) into Syria to conduct counter-terrorism operations.
“But it doesn’t give them (Turkish troops) the right to remain on Syrian territory permanently and we are opposed to Turkish troops staying on Syrian territory permanently,” he said.
But has Russia given any sign they'll militarily support Assad's army move north against Turkey? That would basically mean war between the two countries, and I think Russia doesn't want that.
Russia has also reportedly agreed to establish a no-fly zone over northern Syria.
I'm not sure Turkey would agree with that, and if they don't how is that not going to lead to the two air forces fighting each other?