The US says it is "deeply concerned" about the electoral process in Nicaragua a day after Daniel Ortega, the left-wing leader, won a third consecutive presidential term.
A State Department spokesman said the election process was flawed and could not be seen as free and fair.
He said the Ortega government had side-lined opposition candidates and limited monitoring of the polls.
Daniel Ortega won 72.5% of the vote with 99.8% of the ballots counted.
His closest rival, centre-right candidate Maximino Rodriguez, only received 14.2% of the vote.
The State Department's Mark Toner said the Ortega government had not invited international election observers, which he said, "further degraded the legitimacy of the election".
"We continue to press the Nicaraguan government to uphold democratic practices, including press freedom and respect for universal human rights in Nicaragua," he added.
Mr Ortega had been widely expected to win both due to the popularity of his social programmes and because he faced no obvious political challenger.
A former left-wing rebel, Mr Ortega has led Nicaragua through a period of economic stability which has made him popular with the country's business sector and foreign investors.
Who is Daniel Ortega?
- Born in 1946, the son of a shoemaker
- Joined the Sandinista National Liberation Front (FSLN) as a teenager
- 1984: Elected president
- 2006: Wins his second presidential election
- 2011: Wins a third term
- 2016: Wins a fourth presidential election, securing his third consecutive term in office
Supporters of Mr Ortega took to the streets to celebrate his victory.
But even before the first results were announced, members of the opposition coalition Broad Front for Democracy (FAD) called the elections a "farce".
The FAD, which had urged voters to boycott the election, alleged that more than 70% had abstained from voting.
They were contradicted by the electoral authorities which put voter participation at 65.8%.
Mr Ortega's running mate was his wife, Rosario Murillo, who now looks set to become vice-president.
Analysts say that Ms Murillo already shares decision-making with Mr Ortega and could become president if her 70-year-old husband were to bow out.
Nicaragua's economy has grown at double the Latin American average, but the country still needs to attract more foreign investment.
A $50bn (£40bn) plan to build an interoceanic canal across Nicaragua with Chinese investment has gained international attention, but there are serious doubts over whether it will ever be built.
The country has been able to avoid the sky-high murder rates of some of its Central American neighbours but it also faces the ever pervasive threat of drug-trafficking.