* Syrian opposition to shun talks unless goal is Assad exit
* Confident Assad talks of running for re-election next year
* S.Arabia plans to halt cooperation with US on Syria -source
Syria's opposition in exile resisted calls from Western and Arab countries on Tuesday to commit to attending peace talks, saying they would not take part if there was any chance President Bashar al-Assad could cling to power.
Eleven countries meeting in London pressed the opposition National Coalition to join talks to end a conflict that has killed over 100,000 people, but the group listed conditions and said it would decide in the coming weeks whether to attend.
"There will not be any negotiations at all without making sure that the Geneva 2 meeting is basically for the transitional period and for Assad to go," National Coalition chief Ahmed Jarba told a news conference after the London meeting.
"We are not going to sit and negotiate with Assad possibly being there," he said. "Our people would not accept that. They will consider us as traitors if we came here to sell our people."
However, Jarba did not explicitly rule out joining the talks and said his group would meet soon, possibly in Istanbul on Nov. 1, to vote on whether to attend Geneva 2.
The United States and Russia said in May they would convene a "Geneva 2" peace conference in which both sides would agree a transitional political set-up to end the war, but it faces huge obstacles and no firm date has been set.
A communique from Monday's meeting said Geneva 2 would aim to establish a transitional government by which time "Assad and his close associates with blood on their hands will have no role in Syria".
In the latest indication that Assad feels his position is tenable, he said on Monday he saw no reason why he should not run for re-election next year.
British Foreign Secretary William Hague, hosting Egypt, France, Germany, Italy, Jordan, Qatar, Saudi Arabia, Turkey, the United Arab Emirates and the United States, said it was vital that the Western-backed Syrian opposition join the talks.
"We urge the National Coalition to commit itself fully and to lead and form the heart of any opposition delegation to Geneva," he told a news conference.
Many of the mostly Islamist rebels fighting in Syria refuse to recognise the exiled opposition favoured by the West.
U.S. Secretary of State John Kerry said talks were the only possible way to end the war.
"This war will not come to an end on the battlefield ... it will come to an end through a negotiated settlement," he said. "The only alternative to a negotiated settlement is continued, if not increased, killing."
But efforts to present a united front suffered a further setback when it emerged that Saudi Arabia's intelligence chief had said the kingdom would make a "major shift" in relations with the United States in protest at its perceived inaction over Syria and its overtures to Iran.
Prince Bandar bin Sultan has told European diplomats that Washington had failed to act on Syria and other Middle Eastern issues, according to a source close to Saudi policy. "The shift away from the U.S. is a major one," the source said.
There would be no further coordination with the United States over the war in Syria, where the Saudis have armed and financed rebel groups fighting Assad, the source said.
Saudi anger boiled over after Washington refrained from military strikes in response to a poison gas attack in Damascus in August when Assad agreed to give up his chemical arsenal.
Kerry said the Saudis were "obviously disappointed" that the strike on Syria did not take place.
He said President Barack Obama had asked to him to talk to Saudi officials, which he described as "very, very constructive and I am convinced we are on the same page as we are proceeding forward."
Saudi Arabia is also concerned about signs of a tentative reconciliation between Washington and Tehran, the Saudis' old enemy, which may be invited to Geneva.
Saudi Arabia and the United States shared deep concern about Iran's nuclear programme, Kerry said, adding: "I reaffirmed President Obama's commitment that he will not allow Iran to have a nuclear weapon."
Kerry met Saudi Foreign Minister Saud al-Faisal in Paris on Monday regarding Iran.
"I reiterated our position - in any negotiation (with Iran) - that our eyes are wide open, actions are what will speak to us, not words, and no deal is better than a bad deal," Kerry said.
Hague said if Iran were to attend Geneva 2, it must support a proposed interim government as the way to political dialogue and free elections.
"If Iran could start from that position as well as the rest of us, then Iran would be more easily included in international discussions on the subject," he said.
Several officials, including Arab League chief Nabil Elaraby, have said they expect the Geneva 2 conference to convene on Nov. 23, though the United States, Russia and the United Nations have all said no date has been officially set.