ISTANBUL (AFP) - Syria's main opposition coalition reiterated on Saturday its refusal to participate in proposed international peace talks, saying recent developments in the civil war had "closed the doors" to any political initiative.

"What is happening in Syria today completely shuts the doors on any discussions about international conferences and political initiatives," George Sabra, head of the opposition National Coalition,said at a press conference in Istanbul.

His comments referred to an initiative headed by Washington and Moscow to bring the Syrian regime and opposition groups to peace talks in Geneva.

"The war declared by the regime and its allies in the region has reached a level we cannot ignore," Sabra said.

He has already said on May 30 that the opposition would not attend a peace conference while "Iran" and the Lebanese Shi'ite movement Hizbollah were supporting Syrian regime forces on the ground.

"The lives of Syrians are much more important than any political solution of international conference," he said at the time.

Rregime forces captured the last rebel bastion near the flashpoint town of Qusayr, Syrian state television reported on Saturday.

This came after the town of Qusayr, which had been in insurgent hands for a year, fell to the army and forces from Lebanon's powerful Shi'ite Hizbollah movement on Wednesday.

Sabra also accused "Hizbollah and its allies in Syria of destroying the political, social, cultural and humanitarian foundations in the region established thousands of years ago".

He also charged Hizbollah, along with Iraq and Iran, both Shi'ite-majority countries, of pushing towards a "sectarian conflict." But he said the opposition would refuse to be dragged in, saying that this would change "our lives in the region into hell." Assad's regime is dominated by members of the Alawite community, an offshoot of Shi'ite Islam, while the rebels fighting it are mostly Sunni Muslims.

The opposition chief also warned that the Lebanese government would have to take responsibility for the "implications of the invasion" of Syria by Hizbollah, saying the rebellion had the right to defend the Syrian people.

At the same press conference, Coalition Secretary General Mustafa Sabbagh repeated calls for countries backing the uprising to send rebels weapons to match the regime's firepower.

Gen Sabbagh claimed the opposition coalition had done its best to assuage its backers' fears over supplying weapons, receiving "only promises in return, few of which have been honoured."