AMMAN (REUTERS) - Russian air strikes on Syria have killed nearly 1,400 civilians since Moscow started its aerial campaign nearly four months ago, a group monitoring the war said on Saturday (Jan 30).

The Britain-based Syrian Observatory for Human Rights, which collects information from a network of sources on the ground, said the Russian strikes had also killed 965 Islamic State in Iraq and Syria (ISIS) fighters as well as 1,233 fighters from various other insurgent groups.

The main Syrian opposition group heading to Geneva peace talks on Saturday has demanded a halt to a joint Russian and Syrian bombing campaign they say targets mostly civilians in rebel-held areas as a pre-condition for engaging in talks with the Syrian government.

Russia began a major aerial campaign on Sept 30 to help its ally, Syrian President Bashar al Assad. The air strikes tilted the war in Mr Assad's way after major setbacks earlier in 2015 brought rebel groups close to the coastal heartland of his Alawite sect.

Moscow says it is targeting ISIS militants but rebels and residents say the Russian air strikes are causing hundreds of civilian casualties in indiscriminate bombing of civilian areas away from the frontline.