If Iran’s oil exports are cut to zero, international waterways will not have the same security as before, its president said on Wednesday, cautioning Washington against raising pressure on Tehran in an angry confrontation between the longtime foes. The comment by President Hassan Rouhani coincided with a remark by Iranian Foreign Minister Mohammad Javad Zarif that Tehran might act “unpredictably” in response to “unpredictable” U.S. policies under President Donald Trump.