By Adrian Croft BRUSSELS (Reuters) - European Council President Donald Tusk urged European leaders to spend more on defence on Friday as deadly attacks in France, Tunisia and Kuwait drove home his point about dramatic changes to the security situation in Europe and its neighbourhood. Although their talks were overshadowed by the Greek debt crisis, Britain's attempt to renegotiate its membership and a row over migration, European Union leaders also discussed at a Brussels summit how to strengthen Europe's defence industry and how to make Europe a stronger player in the security arena.