The Democratic Republic of Congo's electoral commission vice president resigned on Monday, an election official said, as he faced US sanctions following last year's delayed presidential ballot.
Though the December vote was marred by allegations of rigging, President Felix Tshisekedi beat former leader Joseph Kabila in what was the first peaceful transition of power since independence from Belgium in 1960.
The National Election Commission, known by its French initials CENI, was threatened with US sanctions over delays in releasing accurate vote results from the election.
CENI Vice President Norbert Basengezi has handed in his resignation letter which must be accepted by Tshisekedi and by the head of the election commission, the CENI source said.
Basengezi could not immediately be reached for comment. He was seen as close to former president Kabila.
In March, US Department of Treasury hit Basengezi and two other CENI officials with sanctions charging them with undermining the election process in the DRC.
It accused Basengezi of overseeing CENI officials who used the commission funds for their own political and personal gain.
All three have denied the charges.
The presidential vote was originally planned for 2016 but it was delayed several times and Kabila stayed on beyond the end of his term after the CENI announced the vote would finally be held in 2018.