MOSCOW - Russia accused the United States on Friday of having double standards over the crisis in Syria, saying it had blocked a UN Security Council statement condemning a car bomb attack in Damascus.The car bomb killed 53 people on Thursday on a busy highway close to the Russian Embassy and offices of the ruling Baath Party in the Syrian capital. Russia has been a staunch ally of president Bashar al-Assad.Criticising Washington's position, Russian Foreign Minister Sergei Lavrov told reporters: "We believe this is double standards."