* Activists say security forces shoot dead more protesters
* France wants greater pressure put on Damascus
* Syria could slide into civil war - Clinton
* Total says Syria stops payments for oil output
By Khaled Yacoub Oweis
AMMAN, Nov 18 (Reuters) - Syria is seeking changes to a planned mission to monitor its implementation of an Arab League peace initiative, the group's chief said on Friday, on the eve of a deadline for Damascus to take steps to end months of bloodshed.
Activists said security forces killed 11 people after weekly prayers, in the latest violence in the crackdown on protests against President Bashar al-Assad, which the United Nations says has killed at least 3,500 people since March.
The Arab League has suspended Syria and set the Saturday deadline for it to comply with the Arab peace plan, which entails a military pullout from around restive areas, threatening sanctions unless Assad acts to halt the violence.
Arab League Secretary-General Nabil Elaraby said the organisation was studying a letter from Syria which "included amendments to the draft protocol regarding the legal status and duties of the monitoring mission of the Arab League to Syria".
French Foreign Minister Alain Juppe said he doubted Syria would respond positively to the Arab League initiative. But he said any international intervention must not be unilateral and should be mandated by the United Nations.
U.S. Secretary of State Hillary Clinton feared the country could slide into civil war.
"I think there could be a civil war with a very determined and well-armed and eventually well-financed opposition that is, if not directed by, certainly influenced by defectors from the army," she told NBC news in Indonesia, where she was attending a regional summit.
However, she did not foresee the global community intervening in the same way as it did in Libya. "There is no appetite for that kind of action vis-a-vis Syria," she said, pointing to moves by the Arab League and Turkey.
Juppe, speaking alongside Turkish Foreign Minister Ahmed Davutoglu, said France was ready to work with the Syrian opposition and that tougher sanctions were needed on Damascus.
British Foreign Secretary William Hague will meet Syrian opposition representatives in London next week in what officials characterised as an intensification of contact with Assad opponents.
A Foreign Office source said Britain was "a long way off" from recognising the Syrian National Council or Syrian opposition groups as a government-in-waiting or as the legitimate alternative to Assad.
"What they have to do is come together and form a coherent unified vision of the Syria they want of the future, particularly around the transition period and how to get there," the source said.
Sanctions already imposed by the European Union and the United States are starting to bite: On Friday, French oil major Total said Syria had halted payments for its oil production activities. Syria's oil exports, worth $400 million a month, a vital source of government earnings, have come to a standstill.
But, at the end of a week in which army deserters attacked an intelligence building near Damascus and waged a deadly battle with Assad's forces, Juppe appeared to call on the opposition not to use army defectors to mount attacks.
"We are making a call to the Syrian opposition. To avoid a civil war, we hope that the army will not be mobilised. This would be a catastrophe," Juppe said.
Hundreds of people have been killed in Syria, including civilians, army deserters and forces loyal to Assad, since it agreed on Nov. 2 to withdraw troops from urban areas and release political prisoners under an Arab League initiative.
Syria says it is trying to implement the deal but has called on neighbouring countries to do more to stem a flow of arms to the opposition and end what it says is a media campaign of incitement against Syrian authorities.
On Friday activists said security forces shot dead at least 11 people and wounded dozens when they fired to disperse protests in the cities of Deraa, Homs, Hama and the Damascus suburb of Erbin.
Syria's state news agency said two members of the security forces were killed and a third was seriously wounded when a bomb exploded in the province of Hama. Two others were wounded by gunfire in Deraa, it said.
Syria has barred most independent journalists from the country, making it difficult to verify reports from activists or officials. Authorities blame the violence on foreign-backed armed groups who they say have killed 1,100 soldiers and police.
Protesters called on foreign countries to expel Syrian ambassadors in support of the opposition.
"Whoever fears God should expel the Syrian ambassador" read a banner at a demonstration in the southern province of Deraa, where the uprising erupted in March.
In the eastern province of Hasaka, protesters shouted, "Why are you afraid? God is with us!" In Homs and Hama, young men dancing arm in arm chanted "The Free Army is our army", referring to army deserters who have waged an escalating campaign of attacks on state targets.
Opposition sources said on Wednesday the Free Syrian Army had killed or wounded 20 security police in an assault on an Air Force Intelligence complex on the outskirts of Damascus, the first of its kind in the revolt against Assad.
Russia, which opposed Western efforts to secure a Security Council resolution condemning Syria which could have led to U.N. sanctions on Damascus, said the raid showed that the conflict in Syria was "similar to real civil war".
France, Britain and Germany plan to ask the U.N. General Assembly's human rights committee to approve a resolution condemning the violence in Syria, before putting the non-binding measure to a vote in an assembly plenary session.
Russian Prime Minister Vladimir Putin called on Friday for a cautious response from the international community.
"We are ready to work with the international community but we call for restraint and caution," Putin told reporters, asked whether Russia will support calls for Assad to resign or back a U.N. resolution condemning his actions.
Meeting his French counterpart Francois Fillon in Moscow, Putin chided France for meddling in the affairs of other nations and reiterated a warning against military intervention.
Fillon said that faced with an increasingly "dramatic" situation in Syria, France was "more than ever determined to take action" against a president "who has lost all legitimacy in our eyes by firing on his own people".
Iran's ambassador to Lebanon said growing international pressure would not topple Syria's government.
"These threats will not yield any results," Ghadanfar Roken Abadi said on Friday. "Intensifying these threats...only increases our enthusiasm for popular unity with Syria."