The U.N.'s deputy peacekeeping chief says the United Nations opposes the South Sudan government's plan to hold elections if warring parties are unable to reconcile differences at peace talks now scheduled to start on May 17.

Bintou Keita, who recently visited South Sudan, told reporters Wednesday that high-level shuttle diplomacy is taking place to try to improve prospects for success at the delayed peace talks.

She said government officials raised new elections as a "Plan B" if the talks fail as a way to exit "the dire situation in which the country finds itself."

But Keita said it's clear to the U.N. that from an economic, political and humanitarian perspective, it is "not conducive right now" for South Sudan "to go through any meaningful elections as a Plan B."