President Recep Tayyip Erdoğan spoke with Saudi Arabia's King Salman by telephone on Tuesday about Syrian government and Russian attacks in northern Syria.Erdoğan stressed the alarming nature of the attacks, which he said further aggravate the humanitarian crisis, according to a presidential source.Erdoğan and Salman discussed preparations for the forthcoming summit of the Organization of Islamic Cooperation (OIC) in Istanbul as well as regional developments, the source said under the customary condition of anonymity.They reportedly agreed to work to end attacks targeting opposition forces in Syria and urged the international community to act to secure access for humanitarian aid.