Egypt's military-led government said it was "reviewing" its strategic relationships with the U.S. and other Western governments critical of its crackdown on Islamists, deepening the divide between the Obama administration and Cairo.

Amid expectations of more violence in coming days, the death toll rose on Sunday as dozens of Muslim Brotherhood supporters were killed in Cairo in what the government described as a prison-break attempt. The Islamist movement's leaders called for continued defiance against Egypt's generals,...