Paris: Violent extremists seeking to overthrow Syrian President Bashar Al Assad may instead have hurt negotiations to replace him, frustrating Western diplomats who continue to push for his ouster as a necessary part of a peace agreement in the Mideast nation’s bloody civil war.

Bolstered by infighting among Syrian opposition groups - including some linked to Al Qaida that have jeopardised foreign aid - US officials say Al Assad has a stronger grasp on power now than he did just months ago, when the US and Russia called for a new round of talks to settle the two-and-a-half-year war that has killed more than 100,000 people. Still, US Secretary of State John Kerry said Al Assad’s recent gains do not assure his future in a new government.

How to persuade Al Assad to step down was part of the focus Tuesday at a London meeting of 11 nations from the West and Mideast seeking a negotiated settlement to the war.

“I don’t know anybody who believes that the opposition will ever consent to Bashar Al Assad being part of that government,” Kerry told reporters Monday in Paris where he was participating in talks about another Mideast crisis, between Israel and Palestinian authorities.

“But I do not believe that it is dependent on whether you’re up or down,” Kerry said. “There’s a human catastrophe awaiting the world if you can’t have a negotiated solution.”

Extremist groups, including the Al Qaida-linked cross-border Islamic State of Iraq and the Levant, have hurt the credibility of the fractured opposition to Al Assad and drawn battle lines among once-allied rebel forces.

As a result, that likely has boosted Al Assad’s confidence to resist yielding at the negotiating table, according to a second senior State Department official who spoke on condition of anonymity to discuss the delicate discussions more candidly.

Britain’s Foreign Secretary William Hague acknowledged that the longer the conflict drags on, the more sectarian it becomes.

“I am in no way glossing over or minimising the danger of extremism taking hold,” he told the BBC Monday as leaders gathered in London. “There are people fighting for extreme groups, not necessarily because of extreme views, but because that gives them access to weapons and training and so on - all the more reason why we have to help the moderate opposition in Syria.”

In Paris, Qatari Foreign Minister Khalid Al Attiyah tersely denied a question over whether his Gulf nation has aided terror groups in the fight against Al Assad.

“Anyone who doesn’t know what’s happening in Syria would say that Qatar is supporting radical groups,” Al Attiyah said at the same news conference as Kerry. “Talking about us supporting radical groups or extremist groups, this cannot be true in any way when we’re working with allies closely.”

The senior State Department official accused the Al Qaida group of - knowingly or not - helping Al Assad by hobbling the moderate rebel groups and diverting aid and focus from the battle against his ruling government.

It’s also feared that Al Assad’s recent willingness to let United Nations inspectors examine his government’s chemical weapons stockpile - a cache that earlier this year he denied even existed - has helped his own credibility and worldwide image.

The London talks also seek to assure Syria’s moderate political opposition leaders that they still have widespread foreign support for demanding Al Assad’s ouster, according to a Western diplomat who requested anonymity to discuss the meeting’s agenda before it took place.

Kerry said the negotiations with Al Assad’s government are likely to take place late next month, but would not confirm they have been set for November 23, a date mentioned by other officials.