ADEN, April 20 (Reuters) - Yemeni troops have made advances in an offensive against al Qaeda-linked militants near the southern city of Zinjibar, killing 18 insurgents, the Defence Ministry said on Friday.
It said on its website that the militants were pushed back on Thursday from several positions near Zinjibar, capital of Abyan province, a stronghold of Ansar al-Sharia (Partisans of Islamic Law), a group affiliated with al Qaeda.
Yemen slipped into a state of chaos after the outbreak of protests more than a year ago that ousted former president Ali Abdullah Saleh under a deal brokered by Gulf neighbours.
On Thursday, the ministry said six militants were killed in Zinjibar and seven in Lawdar, another town in Abyan.
More than 200 people have been killed since government forces stepped up attacks on the militants whom it accused of assaulting a military camp near Lawdar last week.
Exploiting weakened central government control, Islamist insurgents have taken control of a number of cities in the territory which is close to key shipping lanes in the Red Sea.
The website said security forces had uncovered an al Qaeda plot to use six vehicles packed with explosives to launch suicide attacks on gas facilities in Belhaf in the southern Shabwa province.
Yemen's oil and gas pipelines have been repeatedly sabotaged, causing disruptions is exports by the small producer.
The government has regularly reported al Qaeda plots to launch further attacks, but it has not been possible to confirm the reports independently.
France's Total gas pipeline to Balhaf was last blown up in March, hours after a U.S. drone attack killed at least five militants.
New President, Abd-Rabbu Mansour Hadi, who took office vowing to fight al Qaeda, is also facing challenges from Shi'ite Muslim rebels in the north and secessionists in the south. (Reporting by Mohammed Mukhashaf; Writing by Firouz Sedarat)