* Parliamentary speaker says election will be on June 3
* President Assad expected to stand for third term
* Foreign critics have called vote a parody of democracy
* Three-year conflict has killed 150,000
(Adds reaction from opposition, background)
BEIRUT, April 21 (Reuters) - Syria set a presidential election for June 3 on Monday, preparing the ground for leader Bashar al-Assad to defy widespread opposition and extend his grip on power days after he said the war was turning in his favour.
The three-year-old rebellion against Assad's rule has killed more than 150,000 people, forced millions to flee their homes and seen the government lose control over swathes of territory. Hundreds more died on Sunday and Monday.
A leading Syrian opposition group said on Monday the election showed the president was divorced from reality.
Western and Gulf Arab countries that back Assad's opponents had called plans for the vote a "parody of democracy" and said it would wreck efforts to negotiate a peace settlement.
United Nations-backed talks in Geneva collapsed in February with both sides far from agreement - not least over the question of whether Assad should go. No date has been set for their resumption.
Monzer Akbik, chief of staff of the president's office of the main Western-backed National Coalition opposition group, told Reuters the election was a sign Assad was unwilling to cooperate on finding a political solution to the conflict.
"This is a state of separation from reality, a state of denial. He didn't have any legitimacy before this theatrical election and he will not after," he said.
"We do not know what actor he is putting up as an opponent but we are not taking this seriously."
Infighting has fragmented the anti-Assad forces during the conflict, and several major opposition figures have not attended the Geneva talks.
PREPARATIONS FOR ASSAD
Assad has not said whether he will stand again, but his allies in Russia and in Lebanon's Shi'ite movement Hezbollah have predicted he will participate and win.
In state-controlled parts of the capital Damascus, preparations for his candidacy have already begun.
Announcing the election on state television, parliamentary speaker Mohamed Jihad al-Laham said requests for nomination would be accepted until May 1. Voting for Syrians outside the country would take place at Syrian embassies on May 28, he said.
Syria's parliament set residency rules for presidential candidates in March, a move that would bar many of Assad's foes who live in exile.
Assad said last week that the conflict had reached a "turning point" due to his forces' military gains against the rebels.
The fighting has continued, with air strikes, gun battles and shelling reported on Monday across the country.
The opposition Syrian Observatory for Human Rights put Sunday's death toll at 273, including dozens in air strikes on the northern city of Aleppo. Fighting killed dozens more in the early part of Monday.
(Reporting by Alexander Dziadosz and Dasha Afanasieva in Istanbul; Editing by John Stonestreet)