Russia’s planned peace talks between Syrian groups will only succeed if the opposition ends its fight against the government, a senior adviser to President Bashar Assad said on Thursday. “The success of the congress depends on the various opposition groups realizing that the time has come to stop the violence, lay down their weapons and engage in a national dialogue,” said Bouthaina Shaaban. The planned congress on Syria, to be held in Russia, is expected to draw up a framework for the future structure of the state, adopting a new constitution, and holding elections under UN supervision.