Russia has demanded an explanation from Recep Tayyip Erdogan after the Turkish president said he had sent troops into Syria to topple the regime of Bashar al-Assad.

The exchange was the first significant sign of friction between Ankara and Moscow since they restored ties this summer and comes as Russian-backed Syrian government forces press an advance into rebel-held areas of Aleppo.

In a speech on Tuesday, Mr Erdogan condemned the international community’s inaction over the deaths of civilians in Syria and said Turkey’s ongoing cross-border incursion was meant to “bring justice” against the “tyrant” Assad.