Muslims gathered for Eid-al-Adha prayers in Port Sudan on Wednesday as fighting raged on in Khartoum and West Darfur.
RSF paramilitary commander General Mohamed Hamdan Daglo announced on Monday a two-day unilateral truce in advance of the Muslim holiday.
Daglo expressed hope the holiday would provide an opportunity for reconciliation among the Sudanese people, acknowledging the challenging humanitarian conditions caused by the war.
In a televised address on Tuesday, General Abdel Fattah Al-Burhan also called for a unilateral ceasefire and called on young men to defend the country by joining the armed forces.
In recent days, fighting has intensified after a series of ceasefire deals agreed at talks led by the United States and Saudi Arabia in Jeddah failed to stick.
According to the United Nations, the conflict is worsening to "alarming levels" in Sudan's west, with Western nations condemning "widespread human rights violations, conflict-related sexual violence, and targeted ethnic violence in Darfur".
Eid al-Adha, or the Festival of Sacrifice, is one of the most important Muslim holidays, marking the culmination of the annual Hajj in Saudi Arabia.
The raging war, scarcity of humanitarian aid and the refugee crisis make for dire celebrations.