The attack came on the second of a five-day humanitarian cease-fire that began nearly seven weeks after the coalition began airstrikes against the rebels, known as Houthis, and their allies.
The officials said the attack took place in the northern Saada province, which is a stronghold of the Iran-backed rebels and the birthplace of their political movement, Ansar Allah.
The officials say the truck was suspected of carrying rebel weapons. They spoke on condition of anonymity because they are not authorised to speak to the media.
Also today, coalition warplanes flew over Sanaa, Saada and the port cities of Aden and Hodeida in what appeared to be reconnaissance flights, said the officials.
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Saudi Arabia and its mostly Sunni Arab partners began the air campaign on March 26 to try to roll back the Houthis and allied military units loyal to former President Ali Abdullah Saleh.
The coalition hopes to restore President Abed Rabbo Mansour Hadi, Yemen's internationally recognized leader, who fled the country in March in the face of the Houthi advance.
The country of some 25 million people has endured shortages of food, water, medicine and electricity as a result of a Saudi-led blockade.
The cease-fire is meant to help ease the suffering of civilians in Yemen, the Arab world's poorest country.
The new UN envoy, Ismail Ould Cheikh Ahmed, left Yemen today, one day after meeting with leaders of Saleh's one-time ruling party. Ahmed has said he intends to meet separately with other political leaders.
"I will do everything I can to bring all Yemenis to the negotiating table at the earliest time possible," he told reporters before boarding a UN aircraft at Sanaa airport.
In a statement late yesterday, Ahmed welcomed the humanitarian truce but noted "with concern" the continued violence in some areas.