The EU enjoined all parties in the country to refrain from violence, adding that election challenges and complaints would be “addressed in an independent and transparent manner".
The European Union and United States have called for a probe into abuses and violence that occurred during the just concluded election in Uganda.
President Yoweri Museveni was declared the winner for a record sixth term in an election that left more than 40 people dead with opposition candidate, Bobi Wine, put under house arrest.
In a statement, the EU Council of Ministers said opposition candidates were harassed by security forces, adding that the media was suppressed by the government while observers' offices were raided during the election.
The EU enjoined all parties in the country to refrain from violence, adding that election challenges and complaints would be “addressed in an independent and transparent manner".
Wine, Museveni's strongest opposition, has consistently claimed that the election was rigged.
The activist has been under house arrest since Friday when the military surrounded his house.
In a tweet on Thursday, he said, "I thank all friends in Uganda and abroad who continue to stand with us until we put an end to this indignity."
Different human rights groups and NGOs have called for Wine's release.
Director of Amnesty International Southern Africa Regional Office, Deprose Muchena, in a statement said, "It is neither a crime to stand for president nor to want to challenge the election results in court.
"This continued confinement is politically motivated and a blatant violation of their human rights. It must be lifted immediately and without any conditions.
"The abuses included killings by security forces, arrests and beatings of opposition supporters and journalists, disruption of opposition rallies, and a shutdown of the Internet."
In the same vein, Jake Sullivan, National Security Advisor to President Joe Biden, described the house arrest as "deeply concerning".
The US State Department had also called for authorities to address election "irregularities'' after the United States ambassador to Uganda, Natalie E. Brown, was blocked by Ugandan security forces from visiting Wine on Monday.