The leader of Syria’s most powerful insurgent group has toured the seized city of Aleppo in a surprise visit, for the first time since the group captured large parts of the city last weekend, as fierce fighting intensifies in the government-led counter-offensive in northern Hama.

The rebels have set their sights on an area where President Bashar al-Assad’s government has long maintained strength.

Syrian rebels advanced toward Hama on December 1 as regime forces “sent large reinforcement” to the governorate, the UK-based Syrian Observatory for Human Rights (SOHR) reported.Rebel forces captured the towns of Kafr Zita,