No point Russia siding with Assad -UK's Hague

* Hague says Geneva accord a step forward

* France, Britain want U.N. resolution if not progress

* Britain says resolution would not be mandate for force

* France's Fabius says arming rebels not directly discussed (Adds British diplomat quote)

By John Irish

PARIS, July 4 (Reuters) - Russia should realise the Syrian crisis is out of control and it is pointless to back President Bashar al-Assad while Western and Arab states seek ways to end the crisis, British Foreign Secretary William Hague said on Wednesday.

Speaking alongside French counterpart Laurent Fabius ahead of a "Friends of Syria" meeting in Paris on Friday, Hague said an accord between the five U.N. Security Council members on a potential transition was a "step forward," but it was now key for international envoy Kofi Annan to ensure it was implemented.

"Russia must understand that the situation in Syria is leading towards a collapse, to terrible and grave violence," Hague told a news conference.

"Even if Assad had a free hand to commit as many crimes as he wished, he is not able to control the situation in Syria. So there is no point anybody standing by the Assad regime."

All parties to Saturday's accord hailed it as "concrete progress" towards resolving the crisis 16 months into the uprising against Assad's rule but there was no timeline for specific actions and no consensus on the key question of whether he must step down.

Both Hague and Fabius said the Annan-brokered agreement, which says a transitional governing body should be formed on the basis of mutual consent, implied Assad would not be part of any transition, yet Russia says there is nothing in the deal that forces Assad to step down.

Britain and France have led calls for Assad to step aside and warned they would seek a U.N. Security Council resolution to ensure the Geneva accord is put into place.

Fabius said that given the gravity of the situation, Paris wanted to see signs of movement "as quickly as possible" or else it would seek a resolution invoking the United Nations' "Chapter VII" provision, which allows the Security Council to authorise actions ranging from sanctions to military intervention.

NO MILITARY INTERVENTION

A senior British diplomat said Britain and France would seek support at Friday's meeting for such a move if there was no progress on Annan's plan, but insisted a U.N. Security Council resolution would not mean a mandate for military action.

The diplomat gave no timeline for recourse to the council.

"The ambition for us would be to get the Security Council to support a Chapter VII resolution, for that to have clear measures in there aimed at increasing pressure on the regime," the diplomat, who spoke on condition of anonymity, said.

"Putting the Annan plan into international law and considering coercive non-military measures such as economic sanctions and travel bans under article 41, which specifically rules out the use of force, is what we're talking about at this stage," the diplomat added, speaking in London.

Paris will host about 100 delegations and organisations in Paris on Friday, including U.S. Secretary of State Hillary Clinton and Turkish Foreign Minister Ahmet Davutoglu, the latest effort to ramp up pressure on Damascus.

Members of Syria's deeply divided opposition are also due to speak at the conference, although it is still not clear who will represent them and which groups will attend after persistent differences came to light earlier this week in Cairo.

Fabius said the meeting aimed to discuss extending existing sanctions to more nations as well as finding ways to provide more humanitarian aid to the Syrian population.

Asked if it was time to also concretely discuss arming insurgents given that Qatar and Saudi Arabia have indicated they were ready to supply rebel forces, Fabius said: "The question of weapons is not directly under discussion, but we know that there are some countries which are giving weapons."

"We regret it, given (that) in Geneva we agreed to not militarise (the conflict)." (Additional reporting by Mohammed Abbas in London; Editing by Michael Roddy)