From the gaggle on Air Force One this morning, with Jay Carney, press secretary to the president:

Can I ask one on a different topic, on Bulgaria and the investigations? There are some reports that the U.S. does believe that Hezbollah was behind the attack. Can you confirm that? Do you have any updates on that?

MR. CARNEY: I can tell you that the President, as I walked back here, after he had made the calls that I told you about and got the briefings that I told you about, was on the phone with the Prime Minister of Bulgaria. I don’t have a readout of that call at this point, but he obviously was getting updated on the situation there and the investigation, thanking the Bulgarian Prime Minister for the cooperation, and offering assistance of the United States in the investigation.

As for those reports, I can tell you that we don’t have any confirmation yet. We are working to assess the facts and, with our partners, to discover who was responsible. It is certainly the case that Hezbollah and Iran have been bad actors, as a general matter. But we’re not, at this point, in a position to make a statement about responsibility.