The process entered its second day on Monday without a prospective winner in sight as Nigerians wait with bated breath to see who succeeds President Muhammadu Buhari, whose eight-year rule at the head of Africa’s biggest democracy is ending.

There are three main contenders in the race for the presidency: veteran politician Bola Tinubu of the ruling All Progressives Congress (APC) party; former Vice President Atiku Abubakar from the main opposition People’s Democratic Party (PDP); and Peter Obi, a third-party challenger from the Labour Party. There is also a wildcard candidate – Rabiu Kwankwaso of the New Nigeria People’s Party (NNPP).

Voting on Saturday was hampered by long delays, equipment failure after the introduction of the Bimodal Voter Accreditation System (BVAS), and reports of voter suppression and violence in some parts of the country including Lagos, Borno and Anambra.

“I am disappointed with the way INEC has conducted this election – it has been poorly conducted and poorly monitored, and there are a lot of irregularities that have led to results manipulation,” Oluwaseyi Elijah, a 26-year-old student, told Al Jazeera in the central Nigerian city of Ilorin.

“I don’t feel good about the situation and I am scared that some people are trying to sabotage this election,” said Elijah, who supports presidential candidate Abubakar.

Across social media networks, hundreds of Nigerians at home and in the diaspora have expressed concerns and grievances with widespread issues.

Many have focused on allegations of irregularities affecting the Labour Party, which is favoured by many of the youth in south and central Nigeria.

Approximately 93.4 million voters registered to vote, with a third of that number being people aged 18-34.

Damilare Kanyisola, a Lagos-based visual artist, had just cast his vote in Lagos Island in the commercial capital when a group of men invaded the polling station to disrupt the process on Saturday.

“We were told that if we are not voting for their candidate we should head home or we would be looking for trouble,” Kanyinsola, who voted for Peter Obi, told Al Jazeera. “Security operatives were around – they did not do anything.”

There is currently no clear frontrunner in the election, but a few surprise results have been announced as fringe parties clinched some parliamentary seats. Obi won in the presidential count for Lagos, which has long been a major stronghold of Tinubu, a former governor of the state.

The presidential race is seen as the most competitive in Nigeria’s political history, with Obi and Kwankwaso posing a credible challenge to the two traditional main parties.

Observers say the election could be an opportunity for a new set of leaders to emerge in Nigeria, displacing establishment candidates, some of whom have been around the political scene since the days of military rule in the 1990s.

However, there is a trust deficit in the electoral system, especially among young people. INEC has spent more than 300 billion naira ($652m) to conduct this year’s election, but there have been a string of logistical errors.

In some cases, voters reported having to volunteer to keep watch overnight at their polling units to ensure voters could cast ballots and to observe the count, because the process started late.

At the Awada Primary School in the city of Onitsha in the southeastern state of Anambra, more than a thousand people waited more than six hours to be accredited and vote. Officials arrived late and could not get the BVAS, which was being used for the first time at the national level, to work.

The joint National Democratic Institute/International Republican Institute (NDI/IRI) observer mission said “logistical failings caused late openings across the country, creating tensions, and the secrecy of the ballot was compromised in some polling units given overcrowding”.

The mission, led by Joyce Banda, former President of Malawi, also pointed out that “foreseeable and avoidable” challenges in the electronic transfer of results and timely upload to INEC’s public portal “continues to undermine citizen confidence at a crucial moment of the process”.

Citizens have been less diplomatic.

“This is not what people expected,” Kanyisola said. “INEC prepared for this election for four years.”

For many, the election is seen as a referendum on the eight years of Buhari’s presidency, which has been marked by economic decline and rising insecurity. More than 130 million Nigerians live in poverty, according to government statistics.

With no presidential candidate having a clear path to victory after early results, experts believe the election might be heading for a runoff.

In order to win in the first round, a candidate has to secure the largest share of votes overall and at least 25 percent of 24 of Nigeria’s 36 states, as well as the Federal Capital Territory – Abuja.