The US State Department Thursday warned Americans travelling abroad of possible violence over a Florida pastor's plans to burn copies of the Quran.

The State Department said there could be anti-US demonstrations in many countries in response to the plans that could turn violent, citing protests that have already taken place in Afghanistan and Indonesia.

'The potential for further protests and demonstrations, some of which may turn violent, remains high,' the department said, urging Americans to avoid demonstrations.

US officials have strongly condemned the plans of Terry Jones and his Dove World Outreach Center church to burn the Quran Saturday to mark the ninth anniversary of the Sep 11, 2001, terrorist attack on the US.

Jones has vowed to proceed despite mounting public pressure to abandon the plans.