CAIRO (AP) — Egypt suffered a massive power outage that halted parts of the Cairo subway, took TV stations off the air and ground much of the country to a halt for several hours Thursday, as officials offered no clear explanation for how the country suddenly lost 50 percent of its power generation.

The blackout came barely three months after Abdel-Fattah el-Sissi, a former army chief, was elected president on promises to restore order after three years of turmoil following the 2011 uprising that toppled long-ruling autocrat Hosni Mubarak.