Turkish prime minister, Recep Tayyip Erdogan and US President Barack Obama exchanged condolences on Wednesday over the recent terrorist attacks in Turkey and the killings of the US ambassador in Libya along with three others of the US Embassy staff. The condolences were exchanged over a phone conversation conducted today, while President Obama said he appreciated Erdogan's warning against falling for provocations related to the attacks on the diplomatic missions of the US and other countries and as well as condemning the violence, Turkey's TRT Radio said. The two presidents confirmed their bilateral cooperation in the coming period regarding the Syrian crisis as well. They agreed a transitional period in Syria should start at nearest possible time. Yesterday, ten Turkish soldiers were killed and 70 others were injured when militants from the Kurdistan Workers' Party (PKK) attacked a military convoy with rocket launchers in Bingol, eastern Turkey.