The report also faulted the operations of the EFCC in prosecuting corruption charges.
The observation was stated in the US 2017 Human Rights Report. It said the Federal Government led by Buhari failed to implement laws against corrupt practices.
The report added that although the government took steps to investigate alleged human rights abuses, "impunity remained widespread at all levels of government."
It said in part, "Although the law provides criminal penalties for conviction of official corruption, the government did not implement the law effectively, and officials frequently engaged in corrupt practices with impunity. Massive, widespread, and pervasive corruption affected all levels of government and the security services.
"The constitution provides immunity from civil and criminal prosecution for the president, vice president, governors, and deputy governors while in office."
The report also faulted the operations of the Economic and Financial Crimes Commission (EFCC) in prosecuting corruption charges. It said the Commission failed to follow due process.
It cited the case of the embattled former National Security Adviser (NSA), Sambo Dasuki, who has been in custody of the Department of State Services (DSS) since 2015, despite court orders demanding his release.
The report listed the most significant human rights issues during the year to include: "Extrajudicial and arbitrary killings; disappearances and arbitrary detentions; torture, particularly in detention facilities, including sexual exploitation and abuse; use of children by some security elements, looting, and destruction of property; civilian detentions in military facilities, often based on flimsy evidence."
The list also included, "denial of fair public trial; executive influence on the judiciary; infringement on citizens’ privacy rights; restrictions on freedoms of speech, press, assembly, and movement; official corruption; lack of accountability in cases involving violence against women and children; trafficking in persons; and early and forced marriages."
The report also berated Nigeria's judicial system, saying it was compromised during the period under review.
The US said the executive and legislative arms of government continued to interfere with the judiciary.
It added, "Although the constitution and law provide for an independent judiciary, the judicial branch remained susceptible to pressure from the executive and legislative branches. Political leaders influenced the judiciary, particularly at the state and local levels.
"Understaffing, underfunding, inefficiency, and corruption prevented the judiciary from functioning adequately. Judges frequently failed to appear for trials.
"In addition, the salaries of court officials were low, and they often lacked proper equipment and training. There was a widespread public perception that judges were easily bribed and litigants could not rely on the courts to render impartial judgments.
"Citizens encountered long delays and received requests from judicial officials for bribes to expedite cases or obtain favorable rulings."
The report is coming at a time the Buhari's administration is under heavy criticisms by prominent and ordinary Nigerians.
Ex-Nigerian leaders including former president Olusegun Obasanjo and former head of state Ibrahim Babangida had at separate times written an open letter to President Buhari, highlighting the failures of his government and urging him not to seek re-election in 2019.
Despite these appeals, Buhari on Monday, April 9, 2018, officially declared he is seeking re-election.