Powerful Shiite cleric Moqtada al-Sadr on Tuesday slammed Iraq's government as corrupt and its leader as a "tyrant" while calling on citizens to vote, days after announcing his exit from politics.

The televised speech seemed aimed at establishing the cleric, who leapt to prominence with his fierce criticism of the 2003 U.S.-led invasion, as a figure above the everyday Iraqi political fray.

Iran's ambassador to Moscow on Monday said Russia could build the Islamic republic a second nuclear power reactor in exchange for massive oil shipments that have raised grave concern in Washington.

Ambassador Mehdi Sanaei said the two close trading partners have been negotiating Iran's delivery of hundreds of thousands of barrels of oil a day since a meeting at a regional summit in September between Russian President Vladimir Putin and his counterpart Hassan Rouhani.

Russia on Monday dismissed U.S. claims that it was "enabling" Syria's President Bashar Assad to stay in power and failing to push for a transitional government that could help end the bloody conflict.

"We have done everything we have promised," Russian Foreign Minister Sergei Lavrov told reporters, referring to Moscow's efforts to get the Damascus regime to hold direct peace talks with opponents.

An Iranian negotiator said nuclear talks with world powers this week would focus on advanced centrifuges and the unfinished Arak heavy water reactor, the official IRNA news agency reported Sunday.

Iran is due to resume talks Tuesday in Vienna with the P5+1 -- Britain, France, the United States, Russia and China plus Germany -- aimed at reaching a comprehensive accord on its controversial nuclear program following November's landmark interim deal.

Austrian Airlines announced on Sunday it will resume flights to Iran in March after it stopped flying to the country early last year for what it said were commercial reasons.

The airline confirmed local media reports that flights to Tehran would resume from March 11, attributing the decision, in a statement on its website, to the "current stability" in the country.

U.N. refugee chief Antonio Guterres visits Iran on Monday for talks with officials on the plight of hundreds of thousands of Afghan refugees, the UNHCR said in a statement.

The visit comes ahead of transition in Afghanistan, where a presidential election is due to take place in April and as U.S.-led NATO forces prepare to leave the country by the end of 2014.

Iran said Wednesday it would not accept longstanding allegations that its nuclear program once had a military dimension without seeing the secret documents on which the charges are based.

"We will not accept any of the (International Atomic Energy) Agency allegations unless its documents are proven and the person who presented them clarifies on what basis we have been accused," Iran's nuclear chief Ali Akbar Salehi was quoted as saying by the Mehr news agency.

Armed forces chief of staff General Hassan Firouzabadi has warned the Islamic republic's arch-foes that Iran is prepared for a "decisive battle" if attacked, Fars news agency reported on Wednesday.

"We are ready for the decisive battle with America and the Zionist regime (Israel)," Fars quoted Firouzabadi as saying.

Despite the political deadlock in Lebanon, officials including Speaker Nabih Berri and Progressive Socialist Party leader MP Walid Jumblat are gearing up to head to foreign countries.

Jumblat had pointed out in comments published in al-Joumhouria newspaper on Wednesday that he has been “reincarnated before his death... and I will be in China currently until a breakthrough is achieved.”

The Iranian and Russian embassies in Beirut went on high alert after obtaining information that extremist groups are plotting to target them, al-Joumhouria newspaper reported on Wednesday.

According to the daily, the two embassies started taking extra ordinary security measures and called for a back up from the Lebanese army.