The attack was the latest in a series of violent incidents marring the cease-fire and came as the rivalry over Yemen between Sunni powerhouse Saudi Arabia and Shiite, non-Arab Iran escalated, with a senior Iranian official directing unusually harsh comments at Riyadh.
The Saudi embassy in Washington said in a statement that the rebels, known as Houthis, have "deliberately" breached the five-day truce, citing seven separate incidents in which forces guarding its border came under attack by rebels using mortars, rockets and sniper fire.
In a letter to the new UN envoy to Yemen, Ismail Ould Cheikh Ahmed of Mauritania, a senior official from Ansar Allah, the Houthis' political arm, said the coalition violated the cease-fire in roughly the same provinces cited in the Saudi complaint -- Aden, Shabwa, Taiz, al-Dhale.
"Everyone carries a large responsibility to pressure the other party and to force it to commit to the respect of the truce," said the statement, signed by Mahdi al-Mashat, Ansar Allah's chief negotiator.
The Houthis last year captured Yemen's capital, Sanaa, and much of the country's north before they marched southward. Also on Thursday, coalition warplanes flew over Sanaa, Saada and the port cities of Aden and Hodeida in what appeared to be reconnaissance flights, said the officials. The officials spoke on condition of anonymity because they were not authorized to speak to the media.