WASHINGTON (AFP) - The United States on Monday (July 1) urged all sides in Hong Kong to avoid violence after protesters ransacked the territory's parliament on the anniversary of its handover to China.

"We urge all sides to refrain from violence," a State Department spokeswoman said.

"Hong Kong's success is predicated on its rule of law and respect for fundamental freedoms, including freedoms of expression and peaceful assembly," she said.

The United States has voiced solidarity with activists who succeeded in blocking - for now - a move by Hong Kong's pro-Beijing authorities to allow extraditions to the Chinese mainland, whose communist system is notorious for meting out harsh justice.

During recent protests, police faced accusations of using excessive violence against protesters after firing tear gas and rubber bullets to break up marches.

On Monday's anniversary of Britain's 1997 handover of the financial hub to Beijing, masked protesters broke away from peaceful crowds and broke into the legislature, daubing its walls with anti-government graffiti.