The U.S. State Department on Sunday ordered nonemergency government personnel to leave South Sudan's capital as tension escalates because of fighting in the north.

The travel advisory issued on Sunday stated that fighting was ongoing and that "weapons are readily available to the population."

An armed group clashed with the country's army on Tuesday, leading to the arrests of two government ministers and a deputy army chief allied to former rebel turned Vice President Riek Machar.

Machar's home was surrounded by the army as his supporters said that the arrests were threatening the country's peace agreement.

South Sudan descended into a civil war from 2013 to 2018, during which more than 400,000 people were killed. President Salva Kiir and Machar, his rival, signed a peace agreement in 2018 that is still in the process of implementation.

On Friday, an attack on a U.N helicopter that was on an evacuation mission in the north complicated the security situation and a U.N rights body said that it was "considered a war crime."

The U.N Commission on Human Rights in South Sudan on Saturday said that the violence in the north and tension in Juba, the capital, was "threatening to derail" South Sudan's peace agreement.

"We are witnessing an alarming regression that could erase years of hard-won progress. Rather than fueling division and conflict, leaders must urgently refocus on the peace process, uphold the human rights of South Sudanese citizens, and ensure a smooth transition to democracy," said the chairperson, Yasmin Sooka.