Somalia\'s Shebab rebels said Thursday they were building defences that would plunge Kenyan forces battling them into an \"endless war.\" As Kenyan forces prepared to assault rebel position after moving into Shebab-controlled southern Somalia last month, army spokesman Major Emmanuel Chirchir warned militants were moving weapons by air and donkeys. \"The Shebab mujahideen will defend Somalia, and will put Kenya into an endless war,\" the Al-Qaeda-linked rebels said in statement. \"We will defeat you like the other major countries that have suffered when they attacked Somalia, you will see the consequences.\" Since Somalia spiralled into civil war in 1991, several foreign armies -- including US forces, UN peacekeepers and a 2006 Ethiopian invasion -- have failed to create stability in the anarchic nation. Chirchir said that the rebels, who he claimed had received three planeloads of arms this week, were now transporting the weapons on donkeys. \"Information reaching us confirms that Al Shebab has resorted to using donkeys to transport their weapons,\" Chirchir said in a statement. \"Thus, any large concentration and movement of loaded donkeys will be considered as Al Shebab activity.\" Kenya has warned residents in 10 southern Somali towns to leave Shebab-held areas ahead of an imminent attack, and on Wednesday sunk a small boat off the southern Somali coast carrying 18 men it said were Shebab fighters. \"The Kenya Navy intercepted the skiff and sunk it killing all the militants,\" Chirchir added. The militants however dismissed the reported air deliveries as an excuse by Kenya to legitimise civilian deaths ahead of the expected assault. \"This is cheap propaganda to legalise the indiscriminate killing of Somalis,\" the Shebab statement added, posted in Somali on an Islamist website. Kenya has said it will probe reports of civilian deaths when its warplanes struck the rebel-held town of Jilib at the weekend, where aid agency Doctors Without Borders said five civilians were killed. Rebels however said they feared that there could be more civilian deaths when Kenya ramps up its military attacks on its positions. \"This is a plan to carry out collective punishment against the Muslim people of Somalia... the killing of civilians at Jilib by Kenya is clear testimony of this,\" the Shebab statement added.