Rebels widely believed to be backed by Rwanda and Uganda stepped up their patrols Monday of this key eastern Congo city that they seized last week, even as a midnight deadline issued by a regional bloc for them to withdraw loomed.

The M23 rebels said Monday they plan to move their headquarters to this city of 1 million later this week, another sign that they do not intend to leave by midnight. Underscoring the chaotic situation, armed rebels guarded the Central Bank of Congo while United Nations peacekeepers stood watch over a gas station. Many shops closed early on Monday and few students attended reopened schools.