this is bbc news. the headlines: there's been widespread anger and frustration during nigeria's closest presidential election in recent memory, as poor organisation and logistical problems led to severe delays at polling stations. there were also reports of violence, including gunshots near a polling station in lagos. the uk and the eu appear to be on the brink of finalising a new deal on post—brexit trading rules covering northern ireland. the british prime minister says he is "giving everything" to secure an agreement, as his government is determined "to get the job done". officials in turkey say they are investigating more than 600 people over sub—standard buildings that collapsed during this month's earthquakes.