PORT HARCOURT (Reuters) - Atiku Abubakar won on Sunday almost half the votes cast in a primary race to become the main opposition challenger to Nigerian President Muhammadu Buhari in next year’s elections, party officials said.

Former Nigerian Vice President Atiku Abubakar attends an interview with Reuters in Abuja, Nigeria May 11, 2018. REUTERS/Paul Carsten

Abubakar, 71 and a former vice president, will stand as the People’s Democratic Party (PDP) candidate.

He scored 1,532 votes to defeat other candidates in the race, including the governor of the northwestern state of Sokoto, Aminu Tambuwal, and Nigeria’s Senate President Bukola Saraki, the officials announced.

“This is a victory for all of us. The task to get Nigeria working again starts now,” Abubakar said in a tweet.

At a party convention on Saturday, the ruling All Progressive Congress (APC) picked Buhari, who took office in 2015, for the February vote.

Political parties had until Sunday to select their candidates. Ex-minister Obiageli Ezekwesili, co-founder of a group to raise awareness about more than 200 girls kidnapped by Boko Haram in 2014, earlier announced that she will also run.

The handling of the economy has already emerged as a major issue at the start of the election cycle in Africa’s top oil producer, which also plays a key role in regional wars against Islamist insurgents.

Nigeria entered its first recession in 25 years in 2016, mainly caused by lower oil prices and attacks in the Niger Delta crude-producing region. It emerged from recession early last year but growth remains sluggish and inflation above the central bank’s single-digit target range.

Abubakar hopes to replicate Buhari’s 2015 feat of winning a presidential election at the fourth attempt after he left the ruling APC party in November and re-joined the PDP a month later.

The ex-vice president, who is from the northeastern state of Adamawa, in May told Reuters he would privatise parts of the state oil company and allow the naira currency to float to attract foreign investment if elected as head of state.

He has long enjoyed support from the business elite in Nigeria’s commercial capital Lagos for his conservative-capitalist ideals and, as vice president in a PDP administration from 1999-2007, implemented a programme of liberalisation in areas including the telecoms sector.

Prior to Buhari taking office in 2015, the PDP had been the only party in power since the west African country’s transition to civilian rule in 1999.

Nigeria is Africa’s most populous nation with some 190 million inhabitants from around 250 ethnic groups spread across a mostly Muslim north and mostly Christian south.

Buhari, in a speech to mark the anniversary of Nigeria’s independence on Oct. 1, sought to reassure voters that next year’s elections would be free and fair after the PDP and international observers raised concerns over the way a gubernatorial vote in the southwestern state of Osun was conducted.