Syria's main opposition bloc urged the U.N. Security Council on Saturday to convene an emergency meeting to examine what it called an army massacre near Homs, where it said 110 people were killed.

"More than 110 people were killed (half of whom are children) by the Syrian regime's forces" in the village of Houla, the Syrian National Council said in a statement.

Russia on Friday called the latest round of talks on the Iranian nuclear standoff "constructive" despite big differences that remain as the parties head for more negotiations in Moscow next month.

"The round was held in a constructive and business-like atmosphere despite the significant differences in approaches that remain," the Russian foreign ministry said in a statement.

More than 70 people were killed across Syria on Friday, monitors said, as tens of thousands of protesters took to the streets and tanks were deployed in the country's second largest city.

The latest flare-up of violence came as Kofi Annan, the U.N.-Arab League envoy to Syria who brokered a repeatedly-violated ceasefire last month, finalised plans to return to Damascus.

Iranian media on Thursday said the chances of tottering talks with world powers continuing after the current Baghdad negotiations are "very low," with several outlets saying Iran had essentially been handed Israeli demands.

A correspondent with Iran's al-Alam network reflecting the Iranian delegation's views in Baghdad said the so-called P5+1 -- the five permanent U.N. Security Council members plus Germany -- had to sweeten incentives for Iran to suspend parts of its disputed nuclear program for talks to go on.

Russia said on Wednesday that Iran was ready to hold serious talks on its nuclear program that could lead to a gradual lifting of sanctions in exchange for broader transparency from Tehran.

"We have a clear understanding... that Iran is ready to agree on concrete actions," Foreign Minister Sergei Lavrov told reporters, without elaborating.

World powers pressing Iran to scale back its nuclear program Wednesday offered a new batch of incentives that however fell short of the sanctions relief sought by Tehran, which made a counter-proposal.

A spokesman for EU foreign policy chief Catherine Ashton, the lead negotiator for the P5+1 -- the United States, Russia, China, Britain, France and Germany -- said its proposals made at the meeting in Baghdad were "of interest to Iran."

Baghdad's airport opened Wednesday morning a day after a dust storm stopped flights, officials said, ahead of talks between world powers and Iran over Tehran's controversial nuclear program.

It had been unclear on Tuesday whether the storm would clear in time for the talks between the five permanent members of the U.N. Security Council -- the U.S., Russia, China, Britain and France, plus Germany -- and Iran.

A senior U.S. official warned North Korea Monday against conducting another nuclear test, saying it would be a "serious mistake" that would incur more sanctions and further isolation.

"I think it will be a serious miscalculation and mistake if North Korea were to engage in a nuclear test," Glyn Davies, U.S. special envoy for North Korea policy, told reporters.

Iran's foreign minister told his German counterpart that Tehran seeks "serious intentions" from both sides at talks with world powers on its nuclear program, state media reported on Saturday.

Russia's non-intervention stance on Syria remained unchanged on Saturday as G8 leaders looked to hammer out a joint declaration to put greater pressure on President Bashar Assad's regime.

"There cannot be any change of regime through force," the Kremlin's Africa envoy, Mikhail Margelov said, adding that G8 leaders meeting at Camp David had yet to agree on the Syria part of their final summit declaration.