"We need absolute silence ... If we have to, we will reach Beirut. We have the patience and we have the strength, we are the strongest army in the world," says Yossi Cohen, a firefighter from Haifa. The Israeli army said it launched a ground offensive in Lebanon and that its forces engaged in clashes on Tuesday. But the UN peacekeeping mission in Lebanon, Hezbollah and a source in the Lebanese army denied any ground incursion had begun. IMAGES AND SOUNDBITES