The international community has to do more to isolate the Syrian regime after the latest "brutal and sickening" massacre in the country, British Prime Minister David Cameron said Thursday.

"We need to do much more to isolate Syria, to isolate the regime, to put the pressure on and to demonstrate that the whole world wants to see a political transition from this illegitimate regime to actually see one that can take care of its people," Cameron told reporters during a quick stop in Oslo.

A U.S. State Department team will visit Moscow this week to discuss the Syria crisis, a top official said Tuesday as Western pressure mounted on Russia to back new action against its Soviet-era ally.

"We are in the process of meeting (U.S. Secretary of State) Hillary Clinton's deputies who work on the Middle East and Syria in particular," Russia's Deputy Foreign Minister Mikhail Bogdanov told the RIA Novosti state news agency.

U.N. chief Ban Ki-moon called on Sunday for broad international talks on the rising Syrian crisis, urging Security Council members to consider Arab League demands for stronger U.N. action in the strife-torn country.

"Our priority at this time is to help the Syrian people...I want to welcome a wider international discussion on the future course of actions," Ban told reporters after a meeting with Organization of Islamic Conference chief, Ekmeleddin Ihsanoglu, in the Saudi port city of Jeddah.

Arab leaders called for U.N. action on Saturday as at least 27 people were killed in Syria amid growing concern that Kofi Annan's peace plan is failing and the country descending into all-out civil war.

Annan himself warned of sectarian warfare, singling out Syrian President Bashar Assad and his regime as key to resolving the conflict.

Arab League Secretary General Nabil al-Arabi said on Saturday he has asked the U.N. Security Council to take strong action in order to protect civilians in Syria.

"I sent a letter to the U.N. Security Council asking it to undertake all necessary measures to protect the Syrian people," Arabi told Agence France Presse shortly before the opening of a meeting of the ministerial committee on the Syrian crisis.

The opposition Syrian National Council on Friday accused Iran of "interference in Syrian affairs" by providing Damascus with military aid, and called for an Arab League and U.N. probe.

"Despite the Syrian regime's crimes... the Iranian regime seems determined to provide it with full military, security, economic and political support," the SNC said in a statement.

U.S. Defense Secretary Leon Panetta said Thursday that any military action in Syria would need backing from the United Nations, but called recent violence "intolerable."

Asked if he could foresee a scenario in which the United States would back military intervention even without U.N. authorization, Panetta said: "No, I cannot envision that."

The Obama administration added new sanctions on a Syrian bank Wednesday as a top White House official said the U.S. wants to economically throttle the regime of Syrian President Bashar Assad and cut off salaries of pro-government thugs blamed for the grisly massacre in Houla.

The Treasury Department said the Syria International Islamic Bank has been acting as a front for other Syrian financial institutions seeking to circumvent sanctions. The new penalties will prohibit the SIIB from engaging in financial transactions in the U.S. and will freeze any assets under U.S. jurisdiction.

China on Wednesday restated its opposition to military intervention in Syria, as Russia sought to halt fresh U.N. Security Council action after a massacre of civilian’s sparked global fury.

"China opposes military intervention in Syria and opposes regime change by force," foreign ministry spokesman Liu Weimin told reporters.

Russia is ready to help Iran build a new nuclear power plant alongside the first one Moscow helped construct in the city of Bushehr, a top official at the state nuclear firm Rosatom said on Tuesday.

"If it is not forbidden and if it is advantageous, if there is indeed a project -- then yes, we are ready," news agencies quoted Rosatom's deputy head Nikolai Spassky as saying while on a visit to Kazakhstan.