Syria's Prime Minister Wael al-Halki escaped unscathed from a bomb attack targeting his convoy in the heart of Damascus on Monday.

The explosion shook the Mezze neighbourhood shortly after 9 a.m. local time, killing six and damaging several vehicles.

A human rights group said one of the dead was accompanying Halki, while the five others were passers-by.

According to state news, the prime minister, seen here at a meeting following the attack, was unruffled by the assault.

Mezze is part of a shrinking "Square of Security" that is home to several military and government institutions as well as residences of Syrian officials.

The capital is being slowly sucked into violence and bloodshed as rebels based in the east broaden attacks on the once-insulated city centre.