Bin Laden was killed in a U.S. raid in Pakistan May 2 and his death brought calls for attacks on the United States. An intelligence official told ABC News, "While there is no credible threat, there is much preparation based on the common-sense consideration of the date."
In an advisory issued late Wednesday, the FBI and the Homeland Security Department warned of "renewed efforts to target Western aviation."
Officials said there are several uncorroborated threats against U.S. Interests, including some on the Internet, but they have low credibility, ABC News reported.
"We assess that such threats are almost certainly aspirational and are not indicative of actual plotting," the law enforcement advisory said.
Fox News Channel reported the European Union issued a report saying the terror threat in Europe over the past year "has evolved" since the deaths of bin Laden and other terrorist leaders.
"[L]one actors or small EU-based groups are becoming increasingly prominent, as is the Internet as a key facilitator for terrorism-related activities," Interpol's EU Terrorist Situation and Trend Report stated. "Al-Qaida's call for individual violent jihad through the execution of small-scale attacks may result in an increase in such attacks. The more al-Qaida's core is under pressure, and the more difficult it becomes to prepare large scale attacks, the more al-Qaida will try to recruit individual supporters in the West to plan and execute attacks."