CAIRO: An Egyptian security official says protesters have thrown firebombs and rocks at police who tried to re-open Cairo's central Tahrir Square, where a sit-in has brought downtown traffic to a standstill for nearly three months.

The official says police came under assault after they tried to remove metal barricades and allow traffic to enter the square at dawn on Tuesday. It remains closed to traffic.

He added that around 70 protesters and street vendors were arrested during the skirmish at Tahrir, the epicenter of anti-government protests in Egypt. He spoke anonymously in line with regulations.

Many Cairo residents complain that the overcrowded capital's already gridlocked traffic has been exacerbated by the sit-in.