An armed separatist group backed by the United Arab Emirates led a rapid march into a resource-rich region of Yemen on

Wednesday, taking over wide sections of the territory in a matter of hours.

The separatist group, called the Southern Transitional Council or the S.T.C., seized control of much of Hadramout, a

province in eastern Yemen, and were battling to secure the region’s oil fields, local residents and the group’s

officials said.

An S.T.C. statement on Wednesday evening described the operation as a battle to “liberate all the soil of our homeland,

South Arabia, and build a modern federal state.”