However, the Moroccans underestimated the strength of the Spanish defences. Supplied from the sea by the Spanish Navy and protected by kilometres of trenches and forward outposts, Sidi Ifni, boasting 7,500 defenders by 9 December, proved impregnable. The siege, lasting into June 1958, was uneventful and relatively bloodless, as Spain and Morocco both concentrated resources on Saharan theatres.