The United States has cancelled its observation of Uganda’s presidential election because most of its accreditation requests were denied and said Thursday’s vote would lack accountability and transparency.

The announcement adds to a chorus of concern over the credibility of the election pitting Yoweri Museveni, one of Africa’s longest-serving leaders, against 10 candidates including opposition frontrunner Bobi Wine, a popular singer.

While previous votes have been marred by crackdowns on the opposition, campaigning this time has been particularly violent. Scores of protesters have been killed and opposition candidates, supporters and campaign staff have been arrested repeatedly.

The European Union says the electoral process has been seriously tarnished by the excessive use of force and its offer to deploy a small team of electoral experts was not taken up.

A coalition representing hundreds of Ugandan civil society organisations said it had filed 1,900 accreditation requests but only 10 had been granted.

“Absent the robust participation of observers, particularly Ugandan observers who are answerable to their fellow citizens, Uganda’s elections will lack the accountability, transparency and confidence that observer missions provide,” the U.S. embassy in Uganda said in a statement.

Museveni’s spokesman Don Wanyama said the African Union and East African Community would deploy observers and he couldn’t remember when Uganda last sent monitors to the United States.

Museveni has dismissed interference by foreign partners saying they don’t understand that Uganda’s strength comes from the ruling National Resistance Movement (NRM) party, the army and the economy.

“We therefore don’t need lectures about anything from anybody. Because there’s nothing we don’t know,” Museveni, wearing a military camouflage jacket, said in a television address on Tuesday evening.

Stéphane Dujarric, spokesman for U.N. Secretary-General Antonio Guterres, said the U.N. human rights office was deeply concerned about the deteriorating situation.

“It’s a concern that we very much share,” he said. “There have been arrests, including limitations of rights, freedom of expression, freedom of assembly.”

Uganda is a Western ally, a prospective oil producer and is considered a stabilising force in a region where war has plagued some neighbours. It contributes the biggest contingent of an African Union force fighting Islamist insurgents in Somalia.

Bobi Wine, whose real name is Robert Kyagulanyi Ssentamu, is one the first opposition politicians to channel the grievances of young people into a viable challenge and this has rattled the NRM, analysts say.

“We are not preparing for the election. We are rushing our friends, our fellow citizens, to hospital because they are being brutalized by the military and the police,” Wine said at the funeral of his driver, who he says was shot dead this week.

With nearly 80% of its people under 30, Uganda has one of Africa’s youngest populations. That means the majority of Ugandans were born after Museveni took power in 1986 following a five-year guerrilla war.

More than a dozen European countries, Britain, Canada and the United States expressed their concern on Tuesday about media freedom and the harassment of reporters.

Reporters covering opposition protests have been attacked by the security forces. Last week, police chief Martin Okoth Ochola said reporters would be beaten for their own good, to stop them going to places where their lives might be at risk.

“It’s hard to say there wont be violence,” said a senior EU diplomat. “Every bit of the security apparatus will be on the streets. Theoretically that brings calm, but I think we know that just brings flashpoints.”

Uganda has also banned all social media platforms and messaging apps until further notice.

Museveni apologised for the inconvenience but said Uganda had no choice after Facebook took down some accounts which backed his ruling party.

“He wants to stop the use of our application, the youth vote application, which he knows functions with the internet,” Wine told Reuters on Wednesday.

In what analysts called a display of force amounting to preventative intimidation, a convoy of armoured military vehicles rolled through predominantly opposition areas of the capital Kampala on Tuesday.

“The systematic attempt to stop free information, to intimidate voters, and to harass opposition candidates means that this is no longer a credible election,” said Nic Cheeseman, a professor of democracy at Birmingham University.