NAIROBI, Kenya (AP) — South Sudan's army chief of staff, who had been proposed for U.N. sanctions and accused of directing last year's fighting in the capital that left hundreds dead, has been removed from his post, a presidential spokesman said Tuesday.

Paul Malong's removal comes after months of government infighting and as ethnic violence in the country's civil war has dramatically increased. Malong has long been considered a hardliner in the government of President Salva Kiir, and diplomats repeatedly have accused him of undermining the country's 2015 peace agreement.

Ateny Wek Ateny told The Associated Press that Malong was removed because he had been in charge for over three years. Ateny called that a violation of army rules.

Lt. Gen. James Ajongo Mawut has been named to replace Malong, who did not answer repeated attempts for comment.

A statement later read out on state television Tuesday night did not provide a reason for the removal. Government officials sought to downplay it, with army spokesman Santo Domic Chol calling it "routine."

Analysts have said tensions between the army under Malong and the National Security Services under Akol Koor have split South Sudan's government.

"Malong is a strong Dinka nationalist and key player in ethnic violence since 2013," Jeremy Konyndyk, a former Obama administration official, told the AP. Both Malong and Kiir are part of the Dinka ethnic group.

Last year, a U.N. panel of experts said Malong had directed the July fighting in the capital, Juba, that killed hundreds and caused a surge in violence across the country.

The United States later led efforts to have the U.N. Security Council sanctions on Malong for violating the country's peace agreement, but the attempt failed.

South Sudan's civil war has killed tens of thousands and created the world's fastest-growing refugee crisis.