A human rights group founded by former US President Jimmy Carter has closed its office in Egypt because of the restrictions on democratic rights.
The Carter Center also said it would not send a mission to observe this year's parliamentary elections.
It cited the "crackdown on dissidents, opposition groups, and critical journalists, together with heightened restrictions on core freedoms".
The organisation opened an office in Cairo after the 2011 uprising.
It sought to support the country's democratic transition after President Hosni Mubarak was deposed.
It also monitored six elections, the last being the presidential poll in May 2014 which was won by former military chief Abdul Fattah al-Sisi.
In July 2013, the then field marshal led the overthrow of President Mohammed Morsi and the subsequent crackdown on the Muslim Brotherhood that has so far seen at least 1,400 people killed.
More than 16,000 others have been detained and hundreds have been sentenced to death, including senior figures in the Brotherhood.
Secular activists have meanwhile been prosecuted for protesting against a law that places restrictions on public gatherings, demonstrations or meetings of more than 10 people.
At least 14 journalists are also behind bars in Egypt, including three from al-Jazeera English who were handed lengthy prison terms in June after being convicted of terrorism-related charges.
The Carter Center said its decision to shut its office in Cairo reflected its "assessment that the political environment is deeply polarised and that political space has narrowed for Egyptian political parties, civil society, and the media".
"As a result, the upcoming elections are unlikely to advance a genuine democratic transition in Egypt. Both Egyptian civil society and international organisations face an increasingly restrictive environment that hinders their ability to conduct credible election observation."
The Carter Center urged the Egyptian authorities to take steps to ensure full protection of people's core democratic rights, including the right to participate in political affairs and the fundamental freedoms of association, assembly and expression,