Islamic State fighters have seized Syrian villages on the outskirts of Aleppo from rival insurgent fighters, a monitoring group said on Friday, despite Russian air strikes that Moscow says have targeted the militant group.
Iran's Revolutionary Guards Corps said separately one of its senior commanders had been killed this week near Aleppo, Syria's main northern city. Iran, an ally of the Syrian government, says it has advisory missions in the country but no military forces.
Islamic State are now within 2 km (1 mile) of government-held territory on Aleppo's northern edge, the closest they have been to the city.
Islamic State said its fighters had captured five villages in its offensive and killed "more than 10 apostates", a term it uses to describe Syrian soldiers and their militia allies.
The UK-based Syrian Observatory for Human Rights said it was the biggest advance by Islamic State since it launched an offensive against rebels in the northern Aleppo countryside near the Turkish border in late August.
Russian jets and warships have been bombarding targets across Syria for 10 days in a campaign which Moscow says is targeting the Islamic State fighters who control large parts of north and east Syria, as well as swathes of neighboring Iraq.
But the campaign appears to have mainly struck other rebel groups, some of which - with Western and Gulf support - had been battling to stop the Islamic State advance across Aleppo province. One of those groups, Liwa Suqour al-Jabal, said the Russian strikes destroyed their main weapons depot.
The Observatory reported a new wave of Russian air strikes on Friday morning in Hama and Idlib, apparently in support of a ground offensive launched this week by Syrian troops and allied militia against rebels.
The offensive has focused around the Ghab Plain, next to Syria's western mountain range which forms the heartland of Assad's Alawite minority, and the main north-south highway between the cities of Hama and Idlib.
Securing those areas would help consolidate Assad's control over Syria's main population centers in the west of the country, far from the Islamic State strongholds in the east.
IRANIAN KILLED
Alongside the Russian air campaign, regional officials have told Reuters that hundreds of Iranian troops have arrived in Syria since late September to take part in ground operations with the Syrian army and Lebanese Hezbollah fighters.
Senior Iranian officials have been in the country for several years.
The Iranian Revolutionary Guard Corps said one of its generals, Hossein Hamedani, had been killed near Aleppo late on Thursday. Hamedani was a veteran of the 1980-88 Iran-Iraq war and was made deputy chief commander of the elite forces in 2005.
Several senior Iranian Guards officers have been killed in Syria since the start of the civil war, which erupted after protests in 2011 against President Bashar al-Assad were put down with force.
Iranian lawmaker Esmail Kosari said Hamedani had played an important role preventing rebel fighters seizing the capital Damascus earlier in Syria's conflict, and had returned for a few days because of his deep knowledge of the country.
The Observatory, which monitors Syria's conflict through a network of sources in the country, said Hamedani was killed near Kweires air base, about 20 miles (35 km) east of Aleppo.
