Libreville - Gabon's opposition leader Jean Ping on Friday called on the police and army to join in his fight against the contested re-election of President Ali Bongo.Ping has repeatedly declared himself the winner of the August election, but Gabon's constitutional court has upheld Bongo's victory."I join you in telling them (security forces): Join us in liberating Gabon", he told a crowd of supporters in Libreville, who refer to him as president-elect.He promised he would soon be sworn into office, and spoke a line from the presidential oath: "I swear to dedicate all my strength to the good of the Gabonese people..."Bongo has already been sworn in, taking his oath in September with a call for unity after the disputed election win that sparked deadly unrest and revealed deep divisions in the oil-rich country.His re-election, which was validated by the constitutional court, is contested by the opposition and the European Union.Direct attacks In its final tally, the court ruled Bongo had won 50.66% of the vote and Ping 47.24%, giving Bongo a paper thin lead to 11 000 votes over his opponent."I will serve only one term and none of my children will be made ministers in the government under my authority. None of my descendants... will succeed me directly as president of the republic," Ping said on Friday. His comments were a direct attack on Ali Bongo who took over from his father Omar Bongo, who ruled for 41 years until his death in 2009.Ping said he wanted to "use all appropriate means to get back the victory stolen from us"."There are limits. If he crosses them, he will be arrested," government spokesman Alain-Claude Bilie-By-Nze said, referring to Ping.Gabon has large oil, mineral and tropical timber resources, and its per-capita national income is four times greater than that of most sub-Saharan nations.But about a third of its population of 1.8 million still live below the poverty line - the result, say specialists, of inequality, poor governance and corruption.