Alessio Vinci: Threat against U.S. Embassy suspected

CNN's Alessio Vinci

(CNN) -- Police in Rome, Italy, told U.S. officials on Wednesday that there may have been a security threat against the U.S. Embassy, according to an embassy spokesman.

This development comes after Italian police arrested four Moroccan nationals in Rome on Tuesday and found a map of Rome with the location of the embassy circled.

CNN Correspondent Alessio Vinci is following the story and spoke Wednesday with CNN's Paula Zahn.

ZAHN: How real was this threat, Alessio, this morning?

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VINCI: Police investigators are only confirming to us that (Tuesday's) arrests took place in a pre-dawn raid just outside of Rome. But they would not tell us whether the suspects are believed to be terrorists or people belonging to any specific terrorist organization. What we know so far is what U.S. Embassy officials are telling us, and that is that after meeting earlier today with officials in Rome, they are working under the assumption that there was a threat against the U.S. Embassy, and that is because investigators during that raid found a map of Rome with the location of the U.S. Embassy circled.

U.S. Embassy officials, however, are saying they do not want to comment further, because, they say, it is an ongoing investigation, and so far, any other comment would be premature. Of course, security at the embassy is very tight. It has been very tight for a long time, ever since especially September 11, so no new security measures have been taken at the embassy as a result of this particular threat.

ZAHN: I know some of these details are kind of murky at the moment, but when they said these guys were armed with a cyanide-based chemical -- in what form was that? Do we know?

VINCI: I understand from media reports it was sort of a white powder, like a container with white powder, and people who know about this chemical also say that it is a chemical that is extremely dangerous, mainly because it is very difficult to detect, and very difficult to smell. If you put this powder, this composite, in water, you won't be able to see it, you won't be able to smell it, you won't be able to taste it, if you drink the water.

So therefore, investigators here are very concerned about what exactly the suspects had been arrested with and what they were going to do with this kind of powder. As you said, they had also been found with the map of the city of Rome with the U.S. Embassy circled, and they also had a map of the underground water system .... So those suspects had the very latest information about where to hit, if indeed they wanted to hit the water main here.