A satellite image confirms that the main temple in the ancient city of Palmyra in northern Syria has been destroyed, the United Nations says.There had been earlier reports of an explosion at the Temple of Bel in Palmyra, which is held by militants from the Islamic State (IS) group.Syria`s antiquities chief had earlier said the basic structure of the 2,000-year-old site was intact.But UN satellite analysts Unosat say the image shows almost nothing remains."Unfortunately, the images we acquired do show that the main building of the temple has been destroyed," Einar Bjorgo, Unosat`s manager, told the BBC early on Tuesday.He added that a set of columns nearby had also been destroyed.A local man told the BBC that only the outer boundary wall and the gateway to the temple remained.On Monday, Maamoun Abdulkarim, the head of the Syrian Department of Antiquities and Museums, had said the Temple of Bel suffered a large explosion, but that he believed most of the site had remained intact.Witnesses had struggled, however, to get close to the site to confirm the extent of the damage.IS has previously targeted historical sites in areas under its control in Iraq and Syria, regarding their ancient temples and sculptures as heretical.The sale of looted antiquities is one of the group`s main sources of funding. It has also been accused of destroying ancient sites to gain publicity. -BBC