The U.S. has stepped up its attacks on Islamic State’s industrial base, striking more than 100 tanker trucks used to transport oil that helps the militant group earn tens of millions of dollars each month, an American military spokesman said Monday.

The strikes, part of a broader campaign that began weeks ago, come as the French government conducts airstrikes against Islamic State in retaliation for the series of attacks in the Paris area Friday that killed more than 120 people. The U.S. is providing intelligence and targeting information to the French military to assist in their new campaign.

Syrian opposition activists said Monday that the round of French airstrikes against Islamic State’s self-proclaimed capital in Syria on Sunday night may not have killed any members of the group that claimed responsibility for the Paris attacks.

Four A-10 Thunderbolt fighters and two AC-130 gunships were used Monday to target as many as 300 trucks used to transport oil for Islamic State in the eastern Syrian city of Deir Ezzour, about 280 miles from Damascus, according to Col. Steve Warren, a U.S. military spokesman in Baghdad. About 115 of the 300 trucks were destroyed in the attack, he said.

“The purpose of the strike was to help cripple ISIL’s oil distribution capabilities, which will reduce their ability to fund their military operations,” Col. Warren said, using another name for Islamic State.