Abuja - Nigeria counted ballots in its closely fought general election on Sunday after failures in controversial new technology pushed voting into a second day, with officials calling for calm in the tense wait for a winner. Military fighter jets and ground troops also pounded Boko Haram fighters in the northeastern state of Bauchi after a series of attacks on polling stations on Saturday and Sunday. Also read: Jega insists results will be out within 48 hours The presidential election in Africa's most populous nation is the closest in the country's history, with the first credible challenge from an opposition party. Jonathan's Peoples Democratic Party (PDP) has been in power since Nigeria returned to civilian rule in 1999 but is being pushed to the wire by former military ruler Muhammadu Buhari. First results could be given from Monday, the head of the country's electoral commission said Sunday night. "Our hope is to be able to declare within 48 hours (of polls closing on Saturday) and hopefully within less time," said Attahiru Jega, chairman of the Independent National Electoral Commission (INEC). The prospect of a democratic transfer of power plus economic woes caused by the slump in global oil prices, concerns about corruption and fears about insecurity has energised the vote. One government spokesman claimed there was a "record turnout" and voting was largely peaceful despite sporadic pockets of unrest mainly in southern states such as the key battleground of Rivers. The technical difficulties, however, set the tone for a potential dispute as the PDP has opposed the use of the devices to authenticate voters, saying they were not sufficiently tested. Buhari's All Progressives Congress (APC) supports the new system as a means of curbing voter fraud that has marred previous elections. 'No shenanigans' Wrangling over the results has already begun after counting on Saturday, some of it by flashlight with Nigeria regularly plunged into darkness by daily power cuts. There has been a flurry of claimed constituency successes from both sides, and APC spokesman Lai Mohammed warned about vote manipulation. "There must be no shenanigans," he said. In the southern state of Rivers, thousands of opposition supporters demonstrated on Sunday to call for the cancellation of the elections locally because of alleged irregularities. At the same time, the ruling PDP has described the failure of the technology to read biometric data such as fingerprints on the president's own voter identity card as a "huge national embarrassment". Jega has conceded there were "challenges" but added: "From our general assessment, out of the 150,000 card readers which we have deployed, only about 450 were affected." The devices were used again on Sunday but voters could also be processed manually if further glitches occurred. Jega told a news conference on Sunday INEC was confident its objective of holding a "free, fair, credible and peaceful" election was "on course". "We appeal to all Nigerians to remain peaceful as they await the return of these results," he added, with fears of a repeat of post-poll violence that in 2011 left some 1,000 people dead. According to Jega, 90 polling units were unable to accredit voters and allow them to vote in Nigeria's financial hub of Lagos in the southwest.