A diesel-powered Indian submarine exploded and sank Wednesday in a Mumbai dock, killing an unknown number of 18 crewmen on board and setting back the navy's ambitious modernization drive.

The fully-armed INS Sindhurakshak, returned by Russia earlier this year after a major refit, is nose-down in the water, with just a small part visible above the surface, the navy said.

U.S. intelligence leaker Edward Snowden said in an interview released Tuesday he chose to divulge details of a vast U.S. surveillance effort to journalists who reported "fearlessly" on controversial subjects.

Snowden, in the interview released by The New York Times, said he chose documentary filmmaker Laura Poitras and Guardian reporter Glenn Greenwald because they were not cowed by the U.S. government.

A proposed international peace conference on Syria that aims to bring together President Bashar Assad's allies and the opposition will probably not happen until October at the very earliest, a top Russian official said.

Russian Deputy Foreign Minister Gennady Gatilov said additional preparatory talks for the meeting will be held between Moscow and Washington at the end of August, and that the diplomatic schedule was already busy for September.

Russian prosecutors on Monday accused protest leader Alexei Navalny of breaking the law by receiving donations from foreign nationals, a claim he denied in a radio interview.

Navalny, 37, a charismatic lawyer and a star speaker at anti-Putin rallies, is running for Moscow mayor against a Kremlin-backed incumbent. He was dramatically released from prison last month to allow him to stand.

Russia's economy minister said on Monday that dramatically slowing growth indicated the country had entered a period of possibly prolonged stagnation but that an outright recession was avoidable.

Alexei Ulyukayev's comments came after the first initial estimate on Friday showed that second-quarter growth slowed to 1.2 percent in annual terms compared with 1.6 percent over the first three months of 2013.

Russian Prime Minister Dmitry Medvedev has reinstated the imperial name of a train station outside Saint Petersburg that is used by tens of thousands of tourists visiting the former palaces of the tsars, state media said Sunday.

Medvedev ordered the train station to use its original name of "Tsarskoe Selo" (Tsar's Village), which it lost almost a century ago in 1918 shortly after the Bolshevik revolution and the fall of the Romanov dynasty, according to a government decree.

Moscow and Washington are in agreement about the need to stage a fresh round of Syria peace talks "as soon as possible,” Russian Foreign Minister Sergei Lavrov said Friday.

"Our opinions are very much the same. Come what may, we need to convene the Geneva 2 meeting as soon as possible," Lavrov told reporters in Washington.

U.S. President Barack Obama said Friday that Russia has adopted a more anti-American attitude reminiscent of the Cold War since Vladimir Putin returned to office as president.

Obama said relations had thawed somewhat while Dmitry Medvedev was Russian president, but that when Putin returned to the Kremlin he "saw more rhetoric on the Russian side that was anti-American, that played into some of the old stereotypes about the Cold War contest between the United States and Russia."

U.S. President Barack Obama on Friday pledged an overhaul of government surveillance, acknowledging rising concerns over citizens' privacy.

Obama said he would ask Congress to review a controversial section of the Patriot Act that allows collection of telephone records and would provide for greater outside oversight.

Russia's growth slowed sharply in the second quarter despite President Vladimir Putin's efforts to reverse the trend before he hosts the G20 summit next month, initial estimates showed on Friday.

The first growth reading from the Federal State Statistics Service dealt a heavy blow to the government by revealing that the economy had expanded in the second quarter of this year from the same period in 2012 at a rate of just 1.2 percent.