Britain's foreign minister hinted at a shift in policy on Syria on Thursday, saying President Bashar al-Assad could be allowed to run for re-election and mentioning a possible "arrangement" with regime ally Russia.

"We were wedded for a long time to the mantra that Assad must go. We haven't at any stage been able to make that happen," Boris Johnson told members of a parliamentary committee in the House of Lords.

Asked if one possible scenario could include allowing Assad to contest a democratic election in Syria supervised by the UN, Johnson replied: "Yes".

"I see downsides and I see risks in us going in, doing a complete flip flop, supporting the Russians, Assad.

"But I must also be realistic about the way the landscape has changed and it may be that we will have to think afresh about how to handle this," he said.

Britain has been one of the harshest critics of Russia's Syria policy and the Assad regime, saying that his departure is a precondition for any resolution in a conflict that has killed more than 310,000 people and forced millions to flee.

Johnson's comments were wide-ranging and sometimes contradictory as he also mentioned the "possibility of an arrangement" with Russia for "getting rid of Assad" and fighting the Islamic State group.

But he added: "There are perils in that approach and it's by no means clear that we would either achieve the end of the Assad regime, nor is it clear that even if we did achieve the end of the Assad regime that Syria would be in a better place".

Russia, Iran and Turkey on Tuesday agreed to bolster a fragile truce in Syria but rebels and Damascus made no progress towards a broader settlement to end the war after talks in Kazakhstan.

Source: AFP