Speaking to reporters after chairing a meeting of the U.K. government's Cobra emergency committee, Cameron said he spoke with his counterparts in the Netherlands, Australia and Malaysia to share the information they had in order to streamline the investigation.
Malaysia Airlines said there were 189 Dutch, 44 Malaysians, 27 Australians, 12 Indonesians, nine Britons, four Germans, four Belgians, three Filipinos, one Canadian and one New Zealander on the flight. There are four passenger who have yet to be identified, but the United States said it is still working on determining whether any of them were Americans. CNN reported late Friday morning that no passenger checked in with American passports, but the government will still investigate to see if any nationals checked in with another passport as a dual citizen.
The U.S. also said Friday that the plane was most likely shot down by pro-Russian separatists who have been embroiled in a conflict with the Ukrainian military. Cameron said if it is confirmed, then those responsible for the tragedy must be held accountable.
"As it seems possible, this was brought down, the those responsible must be held to account and we must lose no time in doing that. It's an absolutely shocking incident. It cannot be allowed to stand. Until we know more, it's not really possible to say much more. We will be working hard to get to the bottom of this."
Notable deaths of 2014 [PHOTOS]
Syrian Al Qaida group executes Lebanese soldier