The US administration is considering issuing advisory to its citizens to be vigilant as they travel in Europe in the wake of fresh al-Qaida threats. State Department spokesman PJ Crowley however declined to comment on the matter but he said the administration remains focused on al-Qaida threats to US interests and will take appropriate steps. American and European officials said in Washington that such a move could have negative implications for European tourism if travellers fear possibility of terror attacks. The officials have not identified any specific targets that terrorists might be considering. They fear the terrorists may be plotting attacks in Europe with assault weapons on public places, similar to the deadly 2008 terror attacks in Mumbai in India.