First Vice President Riek Machar reportedly arrested after armed convoy entered his residence in the capital, Juba.
A doctoral student at Tufts University has been detained by federal agents without explanation, her lawyer said.
US president's announcement prompts swift backlash from trading partners, including the European Union, Canada and Japan
Hamas spokesperson Abdel-Latif al-Qanoua was killed when Israeli fighters jets bombed his tent shelter in Jabalia.