The Saudi-led coalition supporting Yemen's government against Iran-backed rebels said a 48-hour ceasefire ended on Monday and will not be renewed after repeated violations.
The ceasefire came after U.S. secretary of state John Kerry met rebel representatives in Oman and urged the government of Yemeni president Abdrabu Mansur Hadi to sign up.
The truce went on effect on Saturday noon local time (0900 GMT) between Saudi-led coalition and Yemeni dominant Shiite Houthi group controlling most part of north Yemen, including the capital Sanaa.
Earlier on Monday, pro-Hadi forces attacked Houthi rebels and their allies on the western outskirts of Taiz, military officials said.
Fifteen rebels and nine loyalist troops were killed in clashes Sunday night in and around Taiz, military and medical sources said.
Sanaa is controlled by the Iran-allied Houthi movement, which still holds vast swathes of the country despite a almost 20-month military campaign by the Saudi-led alliance aimed at restoring Yemen's exiled government.
Witnesses also reported loud explosions on Monday.
In Aden, Yemeni Prime Minister Ahmed Obaid Bin Doghr said that the Arab Coalition countries have managed to salvage his country from the risks of the sectarian strife.
Yemen's 20-month-old war has left more than 7,000 people dead and almost 37,000 wounded, the World Health Organization announced in its latest toll update.
Elsewhere, pro-Hadi forces said they repelled a rebel attack on their positions in Sarwah, in Marib province, east of the capital.
Sanaa is controlled by the Houthis, who still hold vast swathes of Yemen, despite the Saudi-led military campaign gaining territory and not succeeding in restoring President Abd-Rabbu Mansour Hadi to power.
Both the coalition and Yemen's Saudi-backed government accused the Houthis of committing more than 450 truce violations.
"The Houthi's have gained a commanding position on the ground, and they are not likely to negotiate away their gains".