Iceland closed its main international airport on Sunday after a volcanic eruption. The country's most active volcano, sent ash and smoke twenty kilometers into the air. Airlines were told on Sunday to brace for a possible further spread of ash later in the week.Ash could reach northern Scotland by midday on Tuesday and reach other parts of Britain, western France and northern Spain by Friday if nothing changes. A thick cloud of ash blocked out the daylight at towns and villages at the foot of the glacier, where the volcano lies.