Assad must transfer power and leave Syria - Clinton

Speaking at a news conference in Istanbul, Clinton said Syria will not see peace until Assad departs. Damascus has blamed the armed opposition for the massacre.

"The regime sponsored violence that we witnessed again in Hama yesterday is simply unconscionable. Assad has doubled down on his brutality and duplicity, and Syria will not, cannot be peaceful, stable or certainly democratic until Assad goes. So even as we intensify the sanctions pressure, because as we were meeting in Istanbul, the sanctions working committee of the Friends of the Syrian People was meeting in Washington. The time has come for the international community to unite around a plan for a post-Assad Syria," said Clinton.

She added that the conflict cannot be solved until both the Syrian government and opposition actually implement the UN-backed ceasefire which they accepted earlier this year.

"First, the Syrian government must implement all six points of the Annan initiative including a real ceasefire agreed to and observed by all parties. Second, Assad must transfer power and depart Syria. Third, an interim representative government must be established through negotiation," she said.

International envoy Kofi Annan will present the U.N. Security Council on Thursday with a new proposal in a last-ditch effort to rescue his failing peace plan for Syria where 15 months of violence have brought the country to the brink of civil war.

The new proposal comes as the Syrian opposition as well as Western and Gulf nations seeking the ouster of Assad increasingly see Annan's six-point peace plan as doomed due to the Syrian government's determination to use military force to crush an increasingly militarized opposition.

Clinton urged countries to come to a consensus before giving up on Annan's plan.

"We think it is important for us to give Kofi Annan and his plan the last amount of support that we can muster, because in order to bring others into a frame of mind to take action in the Security Council, there has to be a final recognition that it's not working," said Clinton.

Clinton also commented on Iran's controversial nuclear programme, saying major powers wanted Iran to come to talks on its nuclear programme.

"We want Iran to come to that meeting to begin the serious work necessary to take place in order to reach a diplomatic solution. So we want them to come prepared to take concrete steps, particularly in the area of 20 percent enrichment, and we have said that this is a unified position of the international community and those of us in this negotiation, which includes Russia and China, that in response to their action we're prepared to take actions of our own."

Iran is refining uranium to 20 percent of fissile purity - well above the level required to run nuclear power plants - for what it says will be fuel for a medical research reactor.

But Western officials are worried because the 20 percent level hurdles major technical barriers to reaching the 90 percent - or bomb-grade - threshold and they believe Iran is stockpiling more material than it needs for nuclear medicine.

The United States is willing to work with the U.N. Security Council on a conference over Syria's political future, as long as it starts with the premise that Syrian President Bashar al-Assad gives way to a democratic government.

ISTANBUL, TURKEY (JUNE 7, 2012) (REUTERS) - U.S. Secretary of State Hillary Clinton urged Syrian President Bashar al-Assad on Thursday (June 7) to hand over power and leave his country, condemning a massacre near the town of Hama that opponents have blamed on his supporters as "unconscionable".