Turkish and US officials have begun their first "operational planning" meeting aimed at bringing about the demise of Syrian President Bashar al-Assad's embattled regime, as heavy fighting continued in Damascus and Aleppo, The Telegraph reported.

The meeting is expected to coordinate military, intelligence and political responses to the crisis in Syria where a deadly crackdown on peaceful protests that began in March 2011 has according to activists claimed more than 23,000 lives.

The officials are also due to discuss contingency plans in the case of potential threats including a chemical attack by the regime in Damascus which Washington has called a "red line".

Turkish foreign ministry deputy under-secretary Halit Cevik and US ambassador Elisabeth Jones are leading the delegations made up of intelligence agents, military officials and diplomats at the meeting in Ankara, a Turkish foreign ministry source said.

U.S. Secretary of State Hillary Clinton and Turkey's foreign minister Ahmet Davutoglu announced their plans for such a mechanism to hasten the end of President Bashar al-Assad's regime on August 11.