Press reports suggest strongly that the Israeli jets destroyed a facility near Syria's border with Turkey.
All sorts of details of the operation have "leaked" out, but still the precise nature of the "target" remains unclear.
By far the strongest theory though suggests a North Korean nuclear connection - a linkage which the North Korean authorities have strenuously denied.
The story put about by largely unnamed US sources and backed up by the former US ambassador to the United Nations, John Bolton, is that North Korea - under international pressure to scale down its own nuclear weapons programme - has recently transferred equipment or technology to Syria.
And it is this equipment - possibly at a fledgling research centre - that the Israelis hit.
'Political agenda'
All sorts of questions remain. Experts on North Korea's nuclear programme are highly sceptical about the alleged technology transfer. Joseph Cirincione, director for nuclear policy at the Washington-based Center for American Progress, a liberal think-tank, has gone so far as to describe the story as "nonsense".
