ADEN — Fierce fighting was reported on Monday between Houthi rebels and Popular Resistance fighters loyal to President Abdrabbu Mansour Hadi in Yemen's third city Taiz. The clashes came a day after a UN official said a proposed peace conference for Yemen had been postponed indefinitely. For a second consecutive day, rebels and their allies targeted several Taiz neighborhoods with rocket and tank fire, residents said. “There's a real massacre going on in Taiz” which caused the departure in early 2012 of president Ali Abdullah Saleh who supports the Huthis, resident Bassam Al-Qadhi said. “Saleh has aligned himself with the rebels to take revenge,” he added. Officials in neighboring Daleh province said pro-Hadi fighters had retaken several positions from the rebels, including a military camp, in dawn fighting. Pro-government forces have seized six tanks during the fighting, they said. Clashes were also reported in other southern provinces of Yemen on Monday, including Aden, Shabwa and Abyan. The postponement of the planned UN peace conference came just four days before it had been due to open in Geneva. Yemen's government led by Hadi has demanded the Houthis recognize its authority and withdraw from Yemen's main cities — two points demanded by a UN Security Council resolution last month. "The Geneva meeting has been indefinitely postponed because the Houthis did not indicate their commitment to implement the UN Security Council resolution," Sultan Al-Atwani, an aide to President Hadi, told Reuters by telephone. "Also, what is happening on ground — the attacks on Aden, Taiz, Dalea and Shabwa makes it difficult to go to Geneva," he added, naming southern provinces that have become war zones. — Agencies