* Opposition wants President Assad to cede power
* Broader opposition coalition to decide on talks Monday
* Moderate rebel fighters losing ground in Syrian conflict (Updates with official statement)
By Dasha Afanasieva
ISTANBUL, Jan 4 (Reuters) - An influential bloc within the Western-backed Syrian opposition decided on Saturday to shun talks aimed at ending the nearly three-year conflict, citing the international community's inaction.
The Syrian National Council has opposed attending the Jan. 22 negotiations, dubbed "Geneva 2", because it says world powers have not done enough to force President Bashar al-Assad to cede power.
Assad's forces have recently been gaining ground against the moderate rebel fighters backed by the opposition and he faces little pressure to make concessions. At the same time, radical Islamists distrusted by the West have taken a bigger role in the campaign to oust Assad.
"After looking at the issue from a political, military and humanitarian angle ... the general secretary (the Council's 43-strong decision-making body) failed to see any encouragement or clear agenda based on which the meeting can succeed," it said in a statement, reaffirming a previous decision not to go to Geneva 2 "based on current conditions".
The council is part of a broader opposition coalition which is due to make its final decision on whether to attend the Geneva 2 talks on Monday. The opposition meetings are taking place in Turkey, which strongly backs the anti-Assad campaign.
The council decision to shun Geneva could increase pressure on the fractious coalition - which has said it is ready to attend in principle - but will not necessarily force its hand.
Syria was plunged into civil war after an uprising against Assad erupted in March 2011 and descended into an armed insurgency after the army cracked down on protests.
More than 100,000 people have been killed, more than 2 million refugees have fled abroad and another 6.5 million are displaced inside Syria.
The coalition wants the talks in Switzerland to create a transitional authority for Syria in which Assad plays no role, but his government says it will not surrender power and that the president will remain in control.
The opposition group has also called on authorities to release women and children from Syrian jails and for humanitarian corridors into besieged rebel towns, pleas which the council says have been ignored.
"Nothing has changed since we decided against the talks about a month ago except the situation on the ground has become even more complex and the international community has done nothing to ease the humanitarian crisis," said council member Abdulrahman Alhaj.
Moderate rebel fighters have been losing ground to Assad's forces at the same time as facing increasing pressure from radical groups linked to al Qaeda and a newly formed Islamic Front, which is also fighting Assad.
The president, who a year ago was battling rebels for control of the capital, has regained territory around Damascus and central Syria, backed by Shi'ite Iraqi fighters, Lebanese Hezbollah guerrillas and Iranian military commanders.
"How can the international community expect to influence Assad in political negotiations if it can't even get him to lift blockades?" Alhaj said, referring to large areas which remain under siege with no access to humanitarian agencies. (Editing by Dominic Evans and Gareth Jones)