ROME - Italy has expelled nine suspected Islamist militants so far this year as part of a heightened security alert throughout Europe and could make further expulsions, Interior Minister Angelino Alfano said on Sunday."We have done everything necessary, within the limits of possibility, to guard against the threat," Alfano said, noting that the expulsions had started before the Paris attacks which began on Jan. 7 with the Charlie Hebdo shooting."There have been nine expulsions. I'm not stopping here and with regard to expulsions, we will continue to be extremely tough," he said.He said five Tunisians, one Turk, one Egyptian, one Moroccan and one Pakistani, all of whom had longstanding residence permits, had been expelled. Two had been preparing to travel to Syria to fight with Islamist militant groups, he said.Italian media reported that around 100 suspected Islamist militants were under surveillance in Italy but Alfano said the actual number of cases was higher."There is no black list. There is surveillance work but the numbers concerned are much bigger than 100," he said.