President John Evans Atta Mills has appealed for calm at the various biometric registration centres across the country.The president, touring the southern part of the Volta Region, expressed disappointment at the violence that has characterized the ongoing biometric registration exercise.He was speaking with the chief of Battor, Togbe Dzekli VII in the North Tongu District in the Volta Region.Joy FM’s Seth Kwame Boateng, who traveled with the president, reported that Mills also advised people in the area to do everything possible to maintain peace in the region. Meanwhile flagbearer of the opposition New Patriotic Party (NPP), Nana Akufo-Addo, has condemned Wedneday’s violence attack on two leading members of his party in Odododiodoo constituency.The party’s parliamentary candidate for Ablekuma South, Ursula Owusu and Abu Jinapor, an aide to the flagbearer were assaulted by ‘machomen’ who were allegeded to be supporters of the ruling party’s parliamentary aspirant for Odododiodoo, Nii Lantey Vanderpujie.Police have confirmed the incident and said investigations are underway. Speaking to journalists after registering in his hometown, Kyebi in the Eastern region, Nana Akufo-Addo said it was regrettable that the police have not been able to deal with the violence in that constituency. He said it was not the sole responsibility of political parties and their leaders to ensure democracy is maintained but that “all public servants who are required to protect the Ghanaian people and the Ghanaian state are important in making sure that democracy thrives.”The NPP flagbearer urged his supporters to go out in their numbers and register after he was taken through the exercise.