In all likelihood, the United States is exaggerating threats against embassies in order to change the focus away from domestic surveillance. The government is embarrassed that their unconstitutional spying was discovered and leaked to the American public. By shifting focus away from these programs, the country can make Americans forget about what happened.
Yes, the U.S. is exaggerating threats to embassies to silence critics of NSA domestic surveillance. The U.S. had claimed for 2 years that they had decimated al-Qaeda, but now since they are under criticism for eavesdropping they are claiming that their are immediate threats to embassies and consulates around the world.
Would this information have been released publicly if the NSA surveillance program was never leaked? There are probably always constant threats to U.S. interests as well as those of other Western nations, but they are and always have been easily thwarted. Even if the threats are real, the NSA's domestic surveillance program probably isn't responsible for gathering this knowledge.
Since 9/11 the US has been exaggerating threats on many fronts in order to justify an increasing trend of stripping individual rights and privacy from US citizens. Among these exaggerated threats is the threat to embassies, but really the government has tried to create an environment of continual panic about terrorism in order to scare people into not complaining about the loss of liberty they are experiencing. Highway signs, commercials, news, etc have been a part of an overall trend to keep people worrying about their safety, although in reality a single terrorist attack is minor compared to what occurs in many other countries, and the US is actually a very safe place to live.
How convenient... Massive NSA leaks reveal widespread instances of domestic surveillance, and shortly thereafter the U.S. Closes its embassies due to an al Qaeda terror threat. Coincidence? Probably not. They're just trying to prove that the NSA's programs are working to stop terrorist attacks. I wouldn't be surprised if no such threat existed at all. Nice try, Obama. We're not that stupid.
The Us is not exaggering threats to embassies and all threats need to be taken seriously. Inside the embassies are US citizens who are serving the US, we need to make sure these people are protected properly where ever they are. The idea of spying is not taken lightly by the rest of the world and the threats are real.
It is clear that there are a lot of real threats to the United States. After 911, no one can deny that terrorists are targeting the United States. The continued attacks in Spain, London, and Mumbai have shown that terrorists will attack countries that do not have robust surveillance capabilities.