United Nations Secretary-General Ban Ki-moon has condemned a series of car bombs that ripped central Damascus, the Syrian capital, killing more than 50 people and  injuring at least 200.

The deadliest attack of the day involved a massive car bomb that struck an area near the headquarters of the ruling Baath's party, killing at least 53 people, including students and children.

Ban on Thursday renewed his "call on all parties to end the violence and respect international humanitarian law."

He also conveyed his condolences to the families of the victims.

The government said the attacks were carried out by groups linked to al- Qaeda.

Syrian rebels seeking to recognition as a legitimate alternative to President Bashar al-Assad's rule have ramped up attacks on the capital, attacking checkpoints and firing mortar rounds .

The opposition Syrian Observatory for Human Rights, which reported 61 dead in the car bombing, blamed Assad's government for the attack.

The United Nations estimates that up to 70,000 people have been killed since the uprising against Assad that began almost two years ago.

Nearly 700,000 Syrians have already fled across the border, while four million refugees within the country need humanitarian assistance.

Ban has pressed the international community to take action on Syria, saying the country was "self-destructing."

In response to the recent attacks on Damascus, he reiterated his "firm conviction that resorting to violence and military means will only lead to more suffering and destruction, and that a political solution is the only way out."