ISTANBUL (Reuters) - Turkish Prime Minister Ahmet Davutoglu has accused Syrian forces of committing massacres in and around Aleppo and said Turkey would face a major new refugee crisis if Syria's second city were to fall into his hands. As U.S. warplanes bomb Islamic State forces in parts of Syria, President Bashar al-Assad's military has intensified its campaign against some rebel groups in the west and **rth that Washington sees as allies, including in and around Aleppo. Ankara has been pushing for the U.S. ...