US airstrikes targeting an oil port held by Yemen’s Houthi rebels killed 74 people and wounded 171 others, the group said Friday.

Assessing the toll of US President Donald Trump’s campaign, which began March 15, has been incredibly difficult as the US military’s Central Command so far has not released any information on the campaign, its specific targets, and how many people have been killed, AP reports.

But the strike on the Ras Isa port, which sent massive fireballs shooting into the night sky, represented a major escalation for the American campaign by hitting oil facilities for the first time.

In a statement, Central Command said that “U.S. forces took action to eliminate this source of fuel for the Iran-backed Houthi terrorists and deprive them of illegal revenue that has funded Houthi efforts to terrorize the entire region for over 10 years.”

“This strike was not intended to harm the people of Yemen, who rightly want to throw off the yoke of Houthi subjugation and live peacefully,” it added.