South Sudan’s First Vice President Riek Machar has accused Uganda of breaching a United Nations arms embargo by deploying armoured and air force units into the country and conducting airstrikes.

In a letter addressed to the UN, the African Union, and the regional bloc IGAD, Machar claimed that Uganda’s military intervention violated the 2018 peace deal, which ended a five-year civil war. Uganda, however, stated that it deployed troops earlier this month at the request of the South Sudanese government amid rising tensions between Machar and President Salva Kiir.

The latest tensions come after security forces in early March arrested several senior allies of Machar, following clashes in the country’s northeast between the military and the White Army, an ethnic militia the government accuses Machar of supporting. While Machar’s SPLM-IO party denies any links to the militia, the conflict has raised fears of renewed violence along ethnic lines. The UN has also warned that increasing hate speech in the country could lead to further instability.

In his March 23 letter, Machar urged international pressure on Uganda to withdraw its forces, accusing them of launching airstrikes against civilians. A spokesperson from Machar’s office confirmed the authenticity of the letter.

Ugandan and South Sudanese military officials have yet to respond to the allegations of violating the UN arms embargo, which has been in place since July 2018. Meanwhile, South Sudan’s army allegedly attacked SPLM-IO forces at a camp near the capital Juba on Monday night, according to the party’s military spokesperson, Lam Paul Gabriel. The South Sudanese information minister did not immediately comment on the claim.

Uganda’s parliament retrospectively approved the deployment on March 11, with Defence Minister Jacob Markson Oboth stating that the move aimed to prevent a “security catastrophe” in South Sudan.

Further controversy erupted when Uganda’s military chief, Muhoozi Kainerugaba, posted inflammatory remarks on social media, stating, “I’m tired of killing Nuer,” referring to Machar’s ethnic group. He also demanded Machar kneel before President Kiir. The posts, which were later deleted, have sparked concerns about escalating regional tensions.