US officials say a drone strike in Syria last month has killed Boubaker el Hakim, who is believed to be involved in planning the Charlie Hebdo attack in Paris.
US-led coalition planes destroyed 168 Daesh oil tanker trucks in Syria, the coalition said on Friday, in the largest strike of its kind.
The air blitz is the latest instance of what US officials say has been a successful effort to starve Daesh of revenues
The strikes targetted the truck fleet near Palmyra, Syria on Thursday, said a coalition statement adding that the destruction means lost revenues of about $2 million to Daesh, the estimated value of fuel in the trucks.
The strikes are part of a campaign by the US-led coalition to target oil infrastructure controlled by Daesh, which occupies swathes of territory in Syria and Iraq.
Daesh has been on the backfoot as an Iraqi military campaign with US coalition air support has succeeded in wresting back significant territory, including a series of oil fields.
US officials have shifted from simply bombing oil fields controlled by Daesh to targeting energy infrastructure along the production chain, from processing to storage to transportation, Amos Hochstein, the State Department's energy envoy, said in an interview on Friday.
"This is very easy oil to extract. You don't need to be a genius to do it," he said. "But we're moving them from the 20th century to the 17th, 18th century."
That has increased the cost to Daesh of producing each barrel of oil, and has lengthened the amount of time it takes to get a barrel of oil to market, cutting into its profit margins, he said.
Alongside taxes, ransoms and trading in antiquities, oil has been a major fundraiser for Daesh operations, with US defense officials estimating that it made about $47 million per month from oil sales prior to October 2015.
The group is likely earning roughly a third of what it was from oil sales before October 2015, Hochstein said.
US officials have debated whether to destroy energy infrastructure in Daesh-controlled territory given concerns it would be harder for local populations to recover once the group leaves, Hochstein said.
But he argued that because the group itself sets fire to fields when it is pushed out, and many of the fields will need extensive repair anyway, bombing the infrastructure while it is under the group's control will at least reduce its revenue.
"There is no oil infrastructure that survives a retreating Daesh," Hochstein said. "So I feel, bomb the hell out of it now."
Drone strike in Syria kills "Charlie Hebdo attack planner"
A US drone strike in Syria has killed an Daesh terrorist linked to the January 7, 2015 attack on satirical weekly Charlie Hebdo in Paris, defence officials said on Friday.
Boubaker el Hakim was killed late last month in Raqqa, Daesh's defacto capital in Syria, the officials said, adding he was believed to be involved with planning the attack.
Charlie Hebdo, known for its satirical covers gleefully ridiculing political and religious leaders, lost many of its top editorial staff when brothers Cherif and Said Kouachi, armed with assault rifles and other weapons, broke into an editorial meeting and killed 12 people and wounded 11 others.
The attacks prompted a worldwide solidarity movement, with the "Je Suis Charlie" (I am Charlie) slogan going viral on social media.
Daesh, which has controlled parts of Iraq and Syria in recent years, has lost some territory this year to Iraqis and Syrians supported by a US-led coalition of air strikes and advisers.
Apart from the killings at Charlie Hebdo, Daesh sympathisers around the world have carried out other shootings and bombings of civilians.