Etiquette question

I just got off a conference call with some folks in India. As we were waiting for the call to start, my colleague Chris and I were doing some morning news surfing, and I was reading about the series of bomb blasts that hit the commuter railway in Mumbai. The call was taking longer to set up than anticipated, and we speculated that, although our conference was scheduled with people in Delhi, no doubt the rash of attacks had slowed the evening commute there as well. Once the call began, we wanted to communicate our awareness and empathy about the attacks. But we looked at each other blankly, not quite sure what the etiquette was, or what kind of social platitude one uses for expressing condolences over terrorist attacks. Any suggestions?