The White House says it wasn't aware of the simultaneous pager explosions across Lebanon before the attacks.
Thousands were injured and at least 12 killed when pagers, used by political group Hezbollah, detonated yesterday.
Today —a day later— at least nine people are dead and 300 injured after walkie talkies exploded.
Hezbollah believes Israel is responsible
US correspondent Benji Hyer told Ryan Bridge there was a quick phone call between the defence secretaries of Israel and the US minutes before pagers started exploding.
He says Israel told the United States they would be conducting an operation in Lebanon, but no further details were shared.
LISTEN ABOVE

Gavin Grey: UK correspondent on Russian drone striking train behind Boris Johnson and other dignitaries near Ukraine border
03:02

Vicky Pryce: business correspondent on the UK GDP going up by 0.4 percent
02:53

Alf Filipaina: Auckland Councillor on the launch of the City Rail Link and whether extra police are needed
02:37