BERLIN, March 20 (AFP) - Thousands of extra security forces were mobilised across Europe Thursday to guard borders, transport hubs, embassies and military installations amid fears of terror attacks after the start of a US-led war on Iraq. It was also a case of urging public vigilance without causing panic. In Spain, a member of US President George W. Bush's "coalition of the willing" against Iraq, strategic points like public buildings, power stations, communications centres and major enterprises were under heavy guard. It was business as usual at the US embassy in Britain, Washington's major ally, where measures put in...