A car bomb went off Tuesday in the heart of the Syrian capital Damascus near the old building of Syria's Interior Ministry, the pan-Arab al-Mayadeen TV and local media said.

Reports said there were heavy casualties in the explosion that rocked the time-honored al-Marjeh Square in central Damascus, local media said.

The new building of the ministry is located in the Damascus' district of Kafar Souseh.

The blast came one day after a car bomb blast targeted the convoy of Prime Minister Wael al-Halqi and killed and injured 20 people at least. Al-Halqi, however, escaped unscathed.

Explosions have become increasingly common in Syria with the al- Qaida terror network becoming active on Syrian soil, especially after aligning with the radical Nusra Front.