Russian President Vladimir Putin will fly to Britain a day before next week's G8 summit for talks with David Cameron on the conflict in Syria, the British prime minister announced Wednesday.

The two leaders will meet at Cameron's Downing Street office on Sunday, before heading to Northern Ireland for the summit of Group of Eight nations on Monday and Tuesday.

Several thousand people marched through Moscow on Wednesday to support detained or jailed anti-Kremlin protesters, a day after President Vladimir Putin accused Washington of supporting a protest movement against him.

Led by anti-corruption blogger Alexei Navalny, the protest dubbed the "March Against Butchers" was aimed at supporting twelve activists accused of violence at an opposition rally last year as well as jailed activists.

Russian President Vladimir Putin said on Tuesday that Iran had a right to a peaceful nuclear program but slammed as "unacceptable" its threats against its regional nemesis Israel.

"Iran is in a very difficult region," Putin told a televised question-and-answer session in Moscow.

Russian President Vladimir Putin said Tuesday he had always believed that Syrian strongman Bashar Assad should have implemented political reforms that could have averted the current bloodbath.

But Putin also stressed that he remained firmly opposed to outside intervention and implied that Russia's position on the crisis remained unchanged.

Prime Minister Benjamin Netanyahu has spoken to Russia's Vladimir Putin after Moscow offered to bolster the beleaguered U.N. peacekeeping force monitoring the Israeli-Syrian ceasefire line on the Golan Heights, Netanyahu's office said Sunday.

"We discussed issues linked to Syria where the situation is becoming more complex by the day," Netanyahu said in remarks communicated by his office.

Twelve Russians went on trial in Moscow on Thursday accused of violence at a rally on the eve of President Vladimir Putin's inauguration last year, in a process condemned by critics as a show trial aimed at suffocating dissent.

Ten defendants were participating in the hearing from inside a glass-walled cage known as an "aquarium" while two more, who are not under arrest, were seated on a bench.

Russian President Vladimir Putin said Tuesday Moscow had not yet delivered its sophisticated S-300 missiles to the Damascus regime despite hints from Syrian President Bashar Assad that such shipments had already been made.

"The contract was signed several years ago. It has not been realized yet," Putin said at a joint press conference with EU leaders. "We do not want to upset the balance in the region."

Russia on Tuesday ordered the expulsion of an alleged American CIA agent working undercover at the U.S. embassy who was discovered with a large stash of money trying to recruit a Russian agent.

Russia's Federal Security Service (FSB, ex-KGB) identified the man as Ryan C. Fogle -- third secretary of the political section of Washington's embassy in Moscow -- and said he had been handed back to the embassy after his detention.

Israeli Prime Minister Benjamin Netanyahu is to hold talks on Tuesday with Russian President Vladimir Putin on the conflict in Syria, the Kremlin said, amid concerns Moscow plans to deliver advanced missiles to the Damascus regime.

"During the meeting an exchange of opinion is planned on key aspects of bilateral ties," the Kremlin said in a statement.

Israeli Prime Minister Benjamin Netanyahu will visit Russia for talks with President Vladimir Putin, officials said Saturday, amid concerns Moscow may be about to deliver advanced missiles to Syria.

Putin's spokesman Dmitry Peskov confirmed the visit to Agence France Presse, but declined to give details, although he told the Interfax news agency it was being planned for next week.