The African Union chief, Jean Ping, arrived in Abidjan on Friday to cool down rising tensions in Cote d'Ivoire, one day after more than 12 people were reportedly killed in the city following the Nov. 28 presidential run-off.

The chairman of the African Union Commission made the trip after indicating his readiness to mediate the dispute between incumbent Laurent Gbagbo and former prime minister Alassane Ouattara.

Both candidates claimed to have won the election and have named their prime ministers in a standoff, in which tensions has been escalating.

Ouattara, who is internationally recognized as would be president, calls on people to march on the state broadcaster RTI and the prime minister's office for takeover.

Gbagbo, who enjoys the backing of the military, blames his rival and the UN peace mission in his country for street confrontations.

Security forces reportedly fire live rounds on Thursday at Ouattara's supporters trying to seize the RTI. There has been no official report about casualties, but Ouattara's camp put the death toll at 18 to 30, in addition to 90 people injured in the clashes.

A march on the prime minister's office was planned for Friday. No development has been reported in the economic capital Abidjan, after Thursday's bloodshed. Ouattara urges his supporters to continue the move to take over the government.

Ouattara has the support of the ex-rebel New Forces, which has the control in the northern part of the country. Gbagbo has controlled the southern part including Abidjan since the 2002-2003 civil war.

The election was expected to end the long-standing division, but it runs counter to many well wishers amid violence and danger of resumed conflicts.