A new report from a U.N. expert panel suggests former Ivory Coast President Laurent Gbagbo received substantial ammunition transfers from Sudan as he clung to power during postelection violence two years ago.

The country's U.N. peacekeeping mission has found "several tens of thousands of rounds" of ammunition for assault rifles believed to have been produced in Sudan in 2010 and 2011, according to the report.

Thursday's report also includes a July 2010 memorandum signed by Gbagbo's political party and Sudanese President Omar al-Bashir's National Congress Party that pledges security cooperation, including "mutual assistance in case of external foreign interference."

Gbagbo refused to leave office after losing the November 2010 runoff vote to current President Alassane Ouattara, sparking five months of violence that killed thousands.