Jerome Delay, Associated Press
A police officer wounded by a grenade is carried to safety during heavy clashed in the Musaga district of Bujumbura, Burundi, Monday May 4, 2015. Anti-government demonstrations resumed in Burundi's capital after a weekend pause as thousands continue to protest the president's decision to seek a third term.

BUJUMBURA, Burundi — Burundi's Constitutional Court on Tuesday validated the president's controversial bid for a third term but the deputy president of the court, who fled to Rwanda ahead of the ruling, called it unconstitutional.

The ruling came amid prolonged demonstrations against President Pierre Nkurunziza's decision to seek a third term. At least nine people have been killed in violent confrontations with the police since last week, according to the Burundi Red Cross. Scores have been wounded.

Burundi's constitution says the president is elected by universal direct suffrage for a mandate of five years, renewable one time.

Nkurunziza was first installed as president in 2005 by parliament to lead a transitional government. He won the 2010 presidential election as the sole candidate. Opposition members boycotted, saying they feared it would be rigged.

Constitutional Court Deputy President Sylvere Nimpagaritse joined more than 20,000 Burundians who have fled to Rwanda fearing political violence and said he would not rubber-stamp an endorsement of Nkurunziza's re-election bid.

"As a Burundian and custodian of the law, my conscience could not allow me to be part of something all Burundians were standing up against, something that violates the constitution and the pillars upon which peace was achieved in Burundi," Nimpagaritse told The Associated Press in a telephone interview from Rusizi, Rwanda.

Rwanda's government says it is concerned over "the deteriorating situation" in Burundi.

"We appeal to leaders of Burundi to do everything in their power to bring the country back to a peaceful situation ... While we respect Burundi's sovereignty in addressing internal matters, Rwanda considers the safety of innocent population as a regional and international responsibility," Rwandan Foreign Minister Louise Mushikiwabo said.

The U.S. has criticized Nkurunziza's decision to seek a third term.

Evelyne Butoyi, who is in charge of information for Burundi's ruling party, said the court reached the decision in support of the ruling party on Tuesday.

Burundi's defense minister, Maj. Gen. Pontien Gaciyubwenge, said on Saturday that the army should remain neutral amid the unrest. He urged "all political actors" to avoid violence.

Edmund Kagire in Kigali, Rwanda contributed to this report.