CAIRO -- A rare drone attack on Sudan’s capital killed three children Monday, a rights group said, as both sides in the country’s war step up airstrikes that have killed dozens of civilians in the Kordofan region in recent days.

The strike, which the group blamed on Sudan’s paramilitary Rapid Support Forces, killed children ages two, four and six in Imtidad Nasser, a neighborhood east of Khartoum’s airport. The RSF has been at war with the Sudanese military for more than three years.

Sayed Mustafa, a resident of the area, told The Associated Press he saw a drone flying toward the airport and heard anti-aircraft fire engage it.

“Shortly after, the drone went down, and we heard an explosion near the airport,” Mustafa said.

Emergency Lawyers, a group that tracks violence against civilians in Sudan’s war, condemned the attack, calling it a humanitarian tragedy and a “serious violation” that requires investigation and accountability.

There was no immediate comment from the RSF.

According to the group, the Sudanese military struck West Kordofan province with drones in a separate attack over the weekend, bombing a market in al-Muglad on Saturday, and struck the Al-Dabab area, also in West Kordofan, on Sunday, killing dozens of civilians, including women and children. It called the attacks violations of international humanitarian law.

Sudan’s war began in April 2023, when simmering tensions between the military and the RSF exploded into open fighting in Khartoum and spread across the country.

The conflict has killed at least 59,000 people, according to conflict monitor ACLED, though aid groups say the true toll is likely higher.

About 13 million people have been displaced from their homes, according to U.N. figures, creating what aid groups call the world’s largest humanitarian crisis.

Across Sudan, 33.7 million people, including 17.3 million children, urgently need aid this year. An estimated 825,000 children face severe acute malnutrition, according to the U.N.

The Integrated Food Security Phase Classification (IPC), a global hunger monitor, warned last week that conflict and drought are worsening food insecurity in Darfur and Kordofan, where two displacement camps recorded malnutrition levels above famine thresholds.

The United States on Friday urged the U.N. Security Council to push for a humanitarian truce and expand an arms embargo on Sudan, but China and Russia opposed widening the embargo.