The Independent National Electoral Commission (INEC) conducted the Presidential and National Assembly elections on February 23 followed by Governorship and State House of Assembly elections two weeks later on March 9.
In a statement released on Thursday, March 21, the US Mission commended Nigerians for their commitment to the democratic process throughout the election season, which has not fully concluded.
However, the Mission noted that there were credible allegations of electoral misconducts that put the integrity of the elections in question.
"As noted by many observer groups in their preliminary reports, we too were disappointed by the low voter turnout as well as credible reports of voter intimidation, vote buying, interference by security forces, and violence in some locations.
"We are saddened by those acts of violence and extend our deepest sympathy to the families of those who lost their lives, including those who worked for the Independent National Electoral Commission (INEC) and the security services," the statement read.
With supplementary elections scheduled to take place in some states on Saturday, March 23, the Mission urged all relevant stakeholders to work towards a free, fair, credible, transparent, and peaceful process.
"We encourage all stakeholders, including INEC, political parties, and the security services, to continue to improve the electoral process for future elections. We look to Nigeria as an important leader on the African continent.
"As a democratic partner of Nigeria, the United States remains committed to working together to achieve our mutual goals of peace and prosperity for the citizens of both our countries," the statement read.
After President Muhammadu Buhari was announced the winner of the presidential election, U.S. Secretary of State, Michael Pompeo, noted the assessments of international and domestic observer missions who affirmed its credibility, "despite localised violence and irregularities".
"We commend all those Nigerians who participated peacefully in the election and condemn those whose acts of violence harmed Nigerians and the electoral process," he said in a March 1 statement.
Ex-US Ambassador condemns electoral process
In an article for the Council on Foreign Relations, John Campbell, a former U.S. Ambassador to Nigeria, said the election sets a bad example for democracy in Africa.
Describing the election as "bad news for democracy", he said it was marred by historically low turnout and credible allegations of rigging.
Buhari won re-election for a second term after polling a total of 15,191,847 votes to beat his closest opponent, Atiku Abubakar, who gained 11,262,978 votes in the February 23 election.
Atiku has branded the election the worst in Nigeria's history and officially filed a petition against Buhari's victory before the Presidential Election Petitions Tribunal.
Despite acknowledging that the process was riddled with several malpractices, Campbell believes Atiku's decision to contest the result in court will most likely fail.