Australia Tuesday updated travel advice for more than 30 European countries after the United States warned of a possible Al-Qaeda-linked plot to attack tourism hotspots.

The foreign affairs department revised bulletins for countries across the continent warning of a potential threat to public transport and landmarks. However, the overall alert levels were left unchanged.

The United States "issued a travel alert alerting US citizens of the potential for terrorist attacks in Europe, including the potential for terrorists to attack public transportation systems and other tourist infrastructure in European countries," the bulletins said.

Japan, Sweden and Britain have also alerted their citizens about possible attacks in Europe after the United States Sunday said extremists may use "a variety of means and weapons and target both official and private interests".

US channel Fox News, citing unnamed intelligence officials, said militants had a list of targets including Paris's Eiffel Tower and Notre Dame Cathedral, and Berlin's Brandenburg Gate.