JOHANNESBURG, South Africa — Sen. Barack Obama canceled a planned visit to Congo at the request of the U.S. Embassy because fighting between rival army factions following presidential elections has stretched embassy personnel, a spokesman said yesterday.

Obama, the son of a Kenyan economist, is on an Africa tour that was to include a trip to Goma in eastern Congo to highlight democracy, elections and the role of peacekeeping.

"There has been a formal request from the U.S. Embassy in Congo to suspend the visit because of violence in Kinshasa that has tied down embassy personnel," a spokesman, Tommy Vietor, said by telephone from the senator's office in Washington.

Obama leaves South Africa today for Rwanda and will fly on directly to Kenya, where he will visit his father's village.

Obama was born in Honolulu, where his parents met at the University of Hawai'i.