Intense fighting continues in and around al-Bab, a town of 100,000 people in northern Syria, with the Free Syrian Army forces supported by the Turks entering from the north, while Syrian regime forces enter from the south.

But when the two forces met at al-Zindin, unconfirmed reports say Turkish tanks were seen supporting the Free Syrian army’s Sultan Murad brigade in clashes with Assad loyalists. The fight to oust ISIL from the city is going to be complicated.

Syria is now split into areas controlled by one of four factions; ISIL, the Syrian government, the Free Syrian army, and the Kurds. Al-Bab is special because it is the only place in Syria where all four have significant forces in close proximity.

It is also a key town on the northern route into Raqqa, ISIL’s self-declared capital.

The clash at al-Zindin was the first between rebels and regime forces in the offensive to retake the city. Russia has intervened at previous flashpoints to prevent the two sides fighting each other, reminding them they have a common enemy, ISIL.