Russia on Sunday welcomed a decision by Syria's opposition to attend an international peace conference next week alongside representatives of a regime they seek to overthrow.

"That is the right decision, we've have always said that one has to go to the forum and enter into dialogue with the government," Deputy Foreign Minister Mikhail Bogdanov told the state ITAR-TASS news agency.

Pro-EU Ukrainians were reinforcing barricades in Kiev on Saturday ahead of a new mass rally, defying President Viktor Yanukovych after he approved strict curbs on protests that caused an outcry in the West.

In a fresh sign of mounting tensions, the president dismissed his chief of staff and will skip this week's economic forum in Davos.

Syria said on Friday it was ready to swap prisoners with the rebels and would take swift steps that could lead to the first such mass exchange in nearly three years of fighting.

The announcement by Syrian Foreign Minister Walid Muallem in Moscow could mark another diplomatic success for Russia after the Kremlin managed to convince its ally Damascus to renounce its chemical weapons in order to avert imminent U.S. air strikes.

A Sudanese migrant froze to death in Estonia in an ill-fated illegal crossing of the EU-Russia border, police said Thursday.

The 54-year-old man and two other surviving Sudanese men crossed a river from Russia to reach Estonia, a member of the European Union since 2004, police spokesman Kerly Peitel told Agence France Presse, noting temperatures had plunged below minus 10 degrees Celsius (14 Fahrenheit).

Georgian Prime Minister Irakli Garibashvili said on Thursday that he was wary about "provocations" from Moscow but confident the ex-Soviet state could withstand any fresh pressure from the Kremlin.

Georgia, which fought a brief 2008 war with Russia over the breakaway region of South Ossetia, initialled a deal for closer ties with the European Union in November and officials in Tbilisi say they hope to ratify the pact later this year.

Three Russian special forces officers were killed Wednesday in a security operation against suspected insurgents in the volatile North Caucasus, the National Anti-Terrorism Committee said.

Russia has stepped up security ahead of the Sochi Winter Olympics next month in the Black Sea resort of Sochi, amid fears of a possible attack organized by insurgents from the North Caucasus.

The United States said Tuesday that it was "disappointed" that Russia had denied a visa to American journalist David Satter, who has written three books on the country.

"The U.S. embassy in Moscow has raised our concerns on this case and the treatment of journalists and media organizations in general with Russian authorities," deputy State Department spokeswoman Marie Harf said.

Hungarian Prime Minister Viktor Orban meets Russian President Vladimir Putin on Tuesday for talks touching on a potentially huge contract for Russia to boost the EU nation's only nuclear power plant.

The Kremlin said in a statement that the two close trade and energy partners were holding "substantive discussions" on building up the capacity of Hungary's Paks facility.

U.S. journalist David Satter, a longtime critic of Russian President Vladimir Putin, said Monday he had been banned from the country in one of the first such expulsions since the Cold War.

Satter, a former Financial Times and Wall Street Journal correspondent who published three books on Russia and the former Soviet Union, had been living and working in the country since September 2013 as an adviser for Radio Free Europe/Radio Liberty.

Tehran is considering a replacement for the Russian S-300 missile defense system, a senior Iranian lawmaker told Fars news agency Monday.

Russia signed a contract with Iran in 2007 to deliver five S-300 advanced ground-to-air missiles -- which can target aircraft or guided missiles -- at a cost of $800 million (590 million euros).