The Britain-based war monitoring group Syrian Observatory for Human Rights, which tracks the conflict via a network of sources in Syria, said Friday that "Islamic State" ("IS") fighters were within a few kilometers of the northern edges of Aleppo.

"IS has never been so close to the city of Aleppo, and this is its biggest advance towards [it]," Observatory spokesman Rami Abdurrahman told the AFP news agency. The monitoring group said several villages close to the city had already been seized from rival insurgents by "IS" since Thursday night. Aleppo is Syria's largest city and before the war was the country's commercial capital.

Forces loyal to Syrian President Bashar al-Assad are positioned just outside Aleppo, in the Shiekh Najjar industrial district. Army cook Mozzafar, 32, who was near Shiekh Najjar, said while civilians in northern parts of Aleppo had moved further south in anticipation of violence, the army was not afraid.

"We have the Russian army and planes to protect us," he told AFP by phone. "We think 'IS' is clever enough not to attack the Syrian army because there would be a huge reaction from Russia."

Battles on many fronts

Russia has carried out its most intense raids in Syria so far in its 10-day air and sea bombing campaign. The Russian Defense Ministry said it had hit more than 60 "terrorist targets" in the past 24 hours. In total, Russia reported killing about 300 militants. Citing intercepted radio communications, the Russian military reported killing two high-ranking Islamic State field commanders. The "IS" gains have been made despite the Russian airstrikes.

The Russian air and sea campaign, which Moscow said targeted "Islamic State," has also struck other anti-Assad groups, some of which are backed by Western and Gulf Arab nations and themselves have been fighting against "IS." Western leaders have accused Moscow of focusing more on boosting its ally Assad, whose forces have launched a ground offensive against rebel groups, than battling IS.

"Daesh has exploited the Russian air strikes and the preoccupation of the (rebel) Free Syrian Army in its battles in Hama, and advanced in Aleppo," one rebel commander with fighters in the region said, using an alternative name for "IS."

Iranian Revolutionary Guard commander Hossein Hamadani was killed in Syria

Separately, a senior Iranian general, Hossein Hamedani, was reported to have been killed near Aleppo late Thursday. Which party is responsible for his death remains unclear.

The war in Syria began in 2011 as an uprising against Assad's rule but quickly escalated into a multi-faceted conflict involving government troops and a host of rebel groups including extremist groups like "IS," Kurdish forces, and Western-backed rebels. Assad's key allies include Russia and Iran, while the United States, Saudi Arabia and several Gulf Arab states have backed the rebels.

The US has been carrying out airstrikes against "IS" in Syria and Iraq for the past year. Washington is due to overhaul its program for training Syrian rebels. The fighting has killed some 250,000 people and forced about 4 million Syrians to flee their country.

se/sms (AFP, AP, Reuters)