Foreign Minister Sergei Lavrov says Russia has not been taking part in discussions with the United States or other countries about a political transformation in Syria that would involve President Bashar al-Assad leaving office.
Lavrov said on June 15 he "read somewhere" that the United States and Russia were discussing a post-Assad Syria.
"This is not true," Lavrov said, adding that Moscow does not "get involved in overthrowing regimes."
French Foreign Minister Laurent Fabius said on June 15 that he believed Russia is anxious about who might take Assad's place if the president was ousted in the conflict against rebels.
Also on June 15, Russia offered a new denial of accusations that it has been selling attack helicopters to the Syrian regime to use in the deadly crackdown on opposition supporters.
In a statement on June 15, the Foreign Ministry said that "many years ago" Russia sold Syria such helicopters, but now Russia was engaged only in repairs of those helicopters.
U.S. Secretary of State Hillary Clinton earlier this week alleged that Russia was supplying attack helicopters to the regime of President Bashar al-Assad.
State Department spokeswoman Victoria Nuland on June 14 sought to clarify, saying helicopters had been repaired in Russia and were sent back to Syria.
Nuland said, however, that whether the Russian helicopters are new or have been refurbished, the Washington remains concerned the aircraft could be used to kill Syrian civilians.
Russia, a longtime Syrian regime ally and arms supplier, has called on both the regime and opposition to implement a United Nations-backed peace plan calling for a cease-fire by all sides.
UN: 'Spike' In Violence
In Syria, the head of United Nations monitors in the country says a spike in violence is hampering the monitors' ability to carry out their mission.
General Robert Mood said on June 15 that violence by both the government and rebel fighters had intensified over the past 10 days, and there were now "significant risks" to the UN observers.
Mood said neither side currently seemed willing to bring about a "peaceful transition" and end the 15-month-old conflict.
In another development, the New York-based rights watchdog Human Rights Watch (HRW) says Syrian government forces have used sexual violence to torture men, women, and children during the Syrian uprising.
HRW said it had interviewed several former detainees who described being sexually abused or witnessing such abuse in detention.
HRW said in a statement that abuse included "rape, penetration with objects, sexual groping, prolonged forced nudity, electroshock and beatings to genitalia."
Sarah Leah Whitson, HRW's Middle East director, said "sexual violence in detention is one of many horrific weapons in the Syrian government's torture arsenal."
HRW said many assaults were in circumstances in which commanders knew or should have known the crimes were happening.
Some interviewees told HRW that victims did not want their families to know about the assault because of fear or shame.
In other news, the White House says President Barack Obama has spoken with King Abdullah of U.S. ally Saudi Arabia.
Officials gave no details about the conversation on June 14, but the talk comes amid heightened concerns over the conflict in Syria and the imminent expansion of sanctions against Iran over the Islamic republic's nuclear program.
Saudi Arabia has been a leading supporter of the Syrian opposition to the Assad regime, and has backed providing foreign help to the rebels.
With reporting by Interfax, AFP, and Reuters