Delhi Police today arrested four people and detained one person in connection with alleged assault on African nationals in South Delhi. The investigators stepped up probe into three separate incidents of assault on African nationals after External Affairs Minister Sushma Swaraj took up the issue with Home Minister Rajnath Singh and Lieutenant Governor Najeeb Jung.<br/><br/>At least six African nationals had sustained injuries in the incidents. Police attributed two of the incidents to a dispute over African nationals playing loud music and another to a scuffle over drinking in public. The incidents came amid outrage over the killing of a 23-year-old Congolese national MK Olivier in south Delhi's Vasant Kunj area last week. India had assured the African envoys of safety and security of all African nationals.<br/>Meanwhile, since yesterday police has held several meetings with various resident associations in the area.