Moscow says the UN should investigate the alleged attack earlier this week, but has also accused the opposition of fabricating evidence of the event.
Allegations of voter fraud in Russia are nothing new. But this time it's the Kremlin making them.
Russian officials are avoiding inflammatory language as they talk about the case of Ryan Fogle, a US diplomat suspected of being a CIA agent.
US Secretary of State Kerry and Russia's Foreign Minister Lavrov say they hope to convene an international conference on Syria later in May. The US has also stepped up humanitarian aid.
The bar is set high, but the US could begin providing body armor, night-vision goggles, rifles, and other basic arms to Syria's rebels.