The United States and Russia are planning to hold a third round of talks on air safety in Syria after it emerged combat aircraft from the two countries flew within 10 miles of each other on Saturday. The United States continues to call for the ouster of Syrian President Bashar al-Assad, and criticizes Russia’s strategy of backing Assad. Meanwhile, officials say the Syrian army and allied Iranian and Hezbollah troops, backed by Russian airstrikes, are preparing a ground offensive against anti-Assad rebels in Aleppo. An anonymous official told Reuters thousands of Iranian troops have been arriving for the offensive.