Saudi-led air strikes hit Yemen’s capital Sanaa overnight targeting forces loyal to former President Ali Abdullah Saleh in the east and south of the city, residents told Reuters on Tuesday.
The strikes are the first to hit the capital after a five-day ceasefire ended late on Sunday, although military operations resumed earlier on Monday in northern Saada province and in the southern city of Aden.
Saudi Arabia and its Sunni Muslim allies have been conducting an offensive against Houthi militants and units loyal to Saleh for more than seven weeks, part of a campaign to restore exiled President Abd-Rabbu Mansour Hadi to power.
The truce ended despite appeals by the United Nations and aid groups for extra time to allow badly needed humanitarian supplies into the country of 25 million people, one of the poorest in the Middle East.
Houthi sources also said they had fired mortar rounds at several areas in Saudi Arabia's southern Najran province late on Monday and that they had engaged in clashes with Saudi forces near the border area.
Houthi rebels have been shelling some populated areas across the borders between Yemen and Saudi Arabia.
The Yemeni crisis has further strained relations between Iran and the Gulf Arab states.
The UN human rights office has so far released a figure of 646 civilian deaths during the Saudi-led air strikes, while 300,000 people are believed to have been displaced, according to the same statistics.
Saudi Arabia and its Gulf allies have been mulling over sending ground forces, but the US have pushed the parties to come closer to a diplomatic solution as Russia and Iran object to Arab moves towards a ground military operation.