SANAA - Fighting rages in Yemen after a United Nations-brokered humanitarian truce came into effect early Saturday as the warring parties were accused of breaching the ceasefire, officials and witnesses said.

Warplanes of the Saudi-led coalition forces struck several military targets in Yemen's capital Sanaa and other major cities early on Saturday, two hours after the truce came into effect, while the Shiite Houthi group fired mortar shells against pro-government fighters in Mansoura neighborhood in the southern port city of Aden, witnesses told Xinhua.

The ceasefire, which was announced Thursday by the U.N. between Yemen's exiled government in Saudi Arabia and the Shiite Houthi group controlling the capital of Sanaa, started on 23:59 (2059 GMT)  on Friday and will last through the end of Muslim holy month of Ramadan on July 17.

It aimed at facilitating aid deliveries to more than 21 million people in Yemen who have been suffered severe shortage in food, water and medicine supplies after more than three months of airstrikes and ground fighting.

The U.N. statement said Thursday that UN Secretary-General Ban Ki-moon had received assurances from Houthis, the General People's Congress, the former ruling party led by ex-President Ali Abdullash Saleh who supported the Houthis, and other parties that "the pause will be fully respected and that there will be no violations from any combatants under their control."(Xinhua)