The convoy of American diplomatic vehicles had just driven a short way into the Gaza Strip when the explosion struck with deadly force.
The bomb blast reduced the jeep to wreckage
The blast went off at 1000 (0800 GMT) near the village of Beit Hanoun, apparently after a bomb hidden in the road was set off by remote control.
A witness at the scene said the explosion struck the third vehicle in the four-car convoy.
It was powerful enough to flip the vehicle over onto its roof, killing its three occupants and leaving a burnt-out wreck.
One of the first reporters to arrive there was Israeli radio journalist Avi Isacharoff, who reached the scene two minutes after the explosion.
He told the BBC: "We heard it when we were about three kilometres from the checkpoint.
"It was completely wrecked. I could not recognise that it was one of the embassy cars. There were pieces of the car all over and pieces of bodies all over."
The BBC's James Rodgers also visited the site shortly after the explosion.
"The car which was hit by the blast is now lying on its roof. You can see American diplomatic plates on it. It's a grey-silver colour.
"The windows of it have been completely destroyed, there's really only just a few remains of the car.
"Clearly this was a very large explosion, you can see fractured parts of the road surface, a hole where the bomb went off."
James Rodgers later witnessed Palestinian youths throwing stones at US officials who went to the scene.
"When the American diplomatic staff arrived, apparently to begin their investigation, the crowd had gathered, and gathered in a close circle around them.
"Some people then began chanting. Then they began throwing stones and the American personnel were forced at that point to withdraw.
"They ran back to their cars with the rocks bouncing off the roof of their cars and the Palestinian security forces then began firing into the air to disperse the crowd, to drive them away, in order to let the Americans leave."