The Saudi-led coalition fighting Houthi rebels in Yemen is taking steps to reduce civilian casualties, the U.S. State Department said on Thursday as it defended a certification to Congress by Secretary of State Mike Pompeo to avoid limits on U.S. aid to the kingdom.

"They are taking steps, in the view of the U.S. government and this administration, in the right direction," State Department spokeswoman Heather Nauert told a briefing. "We see them taking steps. Is it perfect? No absolutely not. Do we see them doing what they can to mitigate civilian casualties? Absolutely we do," she added.

Her comments came a day after Pompeo told Congress that Saudi Arabia and the United Arab Emirates were working to reduce civilian casualties. Without that certification, U.S. tanker aircraft would have been restricted in refueling Saudi coalition planes conducting strikes against the Iranian-backed rebels.