Iran's Foreign Minister has said 60 nations attending a two day nuclear disarmament conference in the Iranian capital have called on Israel to join the Nuclear Non-Proliferation Treaty. <br/> <br/>Israeli Prime Minister Benjamin Netanyahu says his nation has learnt that it can achieve peace only if it remains strong and prepared to defend itself. <br/> <br/>He spoke on Sunday at a ceremony in Jerusalem marking Israel's annual memorial day for fallen soldiers and citizens killed in terrorist attacks.<br/>