People fill in a street during a march at an annual protest in downtown Hong Kong Tuesday. Pic: AP.

HONG KONG (AP) -€” An activist group in Hong Kong says police arrested two organizers of a giant pro-democracy rally that attracted thousands of people this week.

The Civil Human Rights Front said Friday two members of the group and a driver also were arrested. It complained the arrests were “political pressure.”

Police did not immediately confirm the organizers had been arrested. The group said the arrests probably were based on complaints Tuesday’s rally obstructed traffic and police work.

The rally was separate from an unauthorized sit-in where numerous participants were arrested. The march and the unauthorized sit-in were sparked by Beijing saying it has ultimate power over Hong Kong despite promising autonomy to the territory through 2047.

Police said about 100,000 people joined in the rally at its peak, while organizers say 510,000.