More than 30 opposition parties in Nigeria said on Monday they are teaming up to try to prevent President Muhammadu Buhari from being re-elected to a second term in power early next year.Representatives of 39 registered political parties, including the main opposition People's Democratic Party (PDP), signed a memorandum of understanding to form an anti-Buhari alliance in the election next February. PDP spokesperson Kola Ologbodiyan told AFP that the accord would enable the opposition "to come together, present one presidential candidate who will oust the incompetent government of President Muhammadu Buhari".Yunusa Tanko, head of one of the parties - the minority National Conscience Party - said the alliance would enable the opposition to "work together to rescue power".* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTER FOLLOW News24 Africa on Twitter and Facebook"It's a grand alliance of 39 political parties. It's an alliance, not a merger. The idea is that we are going to work together as equal," Tanko told AFP.The parties would present a common candidate for all elective posts at all levels up to the presidency, he explained."Every political party will have a chance of being represented in a government of national unity."At the end of it all, we will have a unity government that is acceptable to all members of the group," Tanko said.Buhari, 75, who came to power in 2015, is seeking a second, four-year term of office at elections and has told his party leaders that he would stand for re-election, despite concern about his age and health. Security and corruption Last week Buhari's former ally, Buba Galadima, announced the creation of a group called the Reformed All Progressives Congress (rAPC), which claims to gather disaffected APC members from across the country, with representation at local government and state level as well as in parliament.Galadima accused the former military ruler and his government of failing to deliver on key pledges to improve security and tackle corruption.Buhari's stewardship of Africa's most populous nation has been "a monumental disaster" and the government has shown itself to be "rudderless, inept and incompetent", he added."It has rather imposed dictatorship, impunity, abuse of power, complete abdication of constitutional and statutory responsibilities, infidelity to the rule of law and constitutionalism," he told reporters in Abuja.