Getty/Ben Pruchnie
The row originates from an interview Corbyn made to the BBC following the terrorist attacks in Paris.
He told the BBC that he was "not happy with a shoot-to-kill policy in general," as they are "dangerous" and "counterproductive."
When asked whether he agreed with Corbyn's views on shoot-to-kill, Benn said that in circumstances such as the recent attacks in Paris, it is "perfectly reasonable" to prevent loss of life with lethal force.
"You have to protect people," he said. When the BBC pushed him on the point, he said "I can't speak for Jeremy in relation to the particular circumstances he may have been thinking about."
By distancing himself from Corbyn, Benn is adding more fuel to the row that erupted in the Labour party yesterday.
British police have a policy of shooting to stop a threat. This means that if they encounter a suicide bomber, they will shoot them in the head to kill them and not in one of their limbs to wound them.
Corbyn also told ITV that he "questioned" whether the apparent killing of Mohammed Emwazi, the British member of ISIS commonly called Jihadi John, in a drone strike last week was legal.
Benn's interview will add to the pressure on Corbyn following the weekly meeting of the Parliamentary Labour Party last night. The meeting is held behind closed doors, but journalists were widely briefed on what happened by MPs inside.
The BBC reported that there was "cold fury" in the room, with one MP apparently calling Corbyn a "f****** disgrace." Another MP told the BBC that they felt "physically sick" at Corbyn's comments.
According to the Huffington Post, Corbyn refused to answer John Mann, the MP for Bassetlaw when he asked "are you telling Labour party members if somebody's outside with a Kalashnikov, you are not going to shoot them?" Many of Mann's colleagues banged their tables to show their support for him.
Corbyn's supporters may be able to dismiss Mann's criticism. He's on the political right of the Labour Party, and he strongly criticised Corbyn in the leadership election.
But the refusal of Shadow Foreign Secretary Benn to wholeheartedly back his leader is a sign that there are serious problems with the Labour Party.
Benn is an important figure in the Labour party at the moment, because he is able to connect with both the wing of the Labour party who support Corbyn and those Labour MPs who feel alienated by his left wing policies.
If Benn and other senior MPs start to waver in their support for him, Corbyn could have massive problems holding his party together.