President Recep Tayyip Erdoğan discussed the 'humanitarian tragedy' in Aleppo with his Russian counterpart Vladimir Putin by phone for the third time in a week on Wednesday, and agreed on the need for a ceasefire, presidential sources said.

The sources said that both presidents agreed that aid efforts for the embattled city should be sped up and agreed on intensifying efforts towards a cessation of hostilities.

Located 40 kilometers (25 miles) from the Turkish border, Aleppo is Syria's second-largest city that used to be home to around three million people, mainly Arabs, including 400,000 Turkmens and 200,000 Kurds.

A year after the outbreak of the Syrian revolution in 2011, opposition forces took control of the city's eastern districts.

In 2013, the Assad regime began a campaign of indiscriminate bombardment on the city that has triggered a humanitarian crisis in the war-battered city.The previous calls between the two leaders had covered bilateral ties as well as a "resolution to the Syrian conflict", notably the possibility of "coordinated efforts in the fight against terrorism".

Relations between the two countries hit a low after Turkey downed a Russian warplane for violating its airspace near the Syrian border on Nov. 24 last year. In response, the Russian government announced sanctions on Turkey, including a ban on exports. The normalization process, which began in June, has paved the way for the lifting of sanctions.