What is the fine-grained topic of the following text: Iranian state television aired footage of defense drills taking place in the country's north through Tuesday as President Hassan Rouhani said the nation faces a “war situation” against a “bullying enemy.” The sanctions, re-imposed by President Donald Trump earlier this year, will end all the economic benefits America granted Tehran for its 2015 nuclear deal with world powers. Only return the topic.
Iran's defense drills and economic sanctions due to nuclear deal disputes with US