* Syria's divided opposition wary of Geneva talks
* Confident Assad talks of running for re-election
* No agreement on whether Iran should attend
By Arshad Mohammed and Peter Griffiths
LONDON, Oct 22 (Reuters) - Western nations and their Middle Eastern allies pressed Syria's fractured opposition on Tuesday to join proposed peace talks, although President Bashar al-Assad has made clear he will not step down - which is their condition for participating.
The United States and Russia said in May they would convene a "Geneva 2" conference to try to end a conflict that has killed well over 100,000 people and forced millions from their homes, but it faces huge obstacles and no firm date has been set.
British Foreign Secretary William Hague, hosting the meeting of 11 nations, said beforehand that it was vital that all elements of the Western-backed Syrian opposition join the talks.
"If they are not part of a peace process in Syria then all the Syrian people have got left is to choose between Assad on the one hand and extremists," he told BBC Radio.
However, opposition factions are loathe to discuss anything except the immediate departure of Assad - who said on Monday he saw no reason why he should not run for re-election next year.
And 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 met Ahmad Jarba, the head of the umbrella opposition Syrian National Coalition, before the London talks began, but there was no word on the outcome.
Kerry said on Monday events may have moved in Assad's favour since he and Russian Foreign Minister Sergei Lavrov announced plans for the peace conference five months ago, but that the aim remained to get both sides to choose a transitional government.
NO ROOM FOR ASSAD
"I don't know anybody who believes that the opposition will ever consent to Bashar al-Assad being part of that government," Kerry said, adding:
"If he thinks he is going to solve problems by running for re-election, I can say to him ... this war will not end."
Hague said no military solution existed and urged Syrians to "make the compromises necessary for a peace process to work".
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.
In London, Britain, Egypt, France, Germany, Italy, Jordan, Qatar, Saudi Arabia, Turkey, the United Arab Emirates and the United States were to discuss the agenda for the peace talks and to help the opposition prepare for them, a U.S. official said.
While Washington has said it is open to the possibility of Iran, which has supported Assad, coming to a Geneva conference, Kerry said it was hard to see Tehran playing a constructive role unless it backs the idea of a transitional government.
Hague said Iran must support a proposed interim government in Syria including figures from Assad's administration and the opposition 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.
However, the West and its Arab allies are divided on Iranian involvement. Saudi Arabia, which backs Syria's mostly Sunni Muslim rebels, vehemently opposes any inclusion of Shi'ite Iran, its regional arch-rival.