Some 20,000 people have fled to Chad in the past fortnight due to surging violence in Sudan's western Darfur region, the United Nations said.
The rising numbers have created an alarming situation at the border, said UNHCR, the UN refugee agency, on Tuesday.
UNHCR "is gravely concerned by the rapidly increasing number of Sudanese refugees crossing into eastern Chad, with nearly 20,000 people - mostly exhausted and traumatised women and children - arriving in the past two weeks alone", said Magatte Guisse, the agency's representative in Chad.
"This sudden influx reflects the escalating violence in Sudan's North Darfur region, particularly in and around El-Fasher, which is triggering mass displacement at an alarming pace."
Speaking from Chad's capital, N'Djamena, he told a media briefing in Geneva that refugees were fleeing "brutal attacks" and "widespread terror".
Guisse said most were arriving without food, money or identity documents and reported that homes had been burned to the ground.
From the airport, where Sudanese airlines had resumed flights after the first drone strike on Sunday, "fires broke out in multiple buildings" following the latest explosion, an eye witness says.
Thousands killed, displaced
Sudan's regular army and the paramilitary Rapid Support Forces (RSF) have been locked in a battle for power since April 2023.
The war has killed tens of thousands of people, uprooted 13 million and created the world's largest hunger and displacement crises.
The battle for El-Fasher, the last major city in Darfur to elude RSF control, has intensified in recent weeks as the paramilitaries have sought to compensate for their loss of the Sudanese capital Khartoum last month.
At least 542 civilians have been confirmed killed in North Darfur in the previous three weeks, the UN rights chief said last Thursday, warning the actual death toll was likely "much higher".
"Attacks on civilians in Sudan must end, and safe passage needs to be allowed to those fleeing for their lives," said Guisse.
Chad is one of the world's poorest countries.
Guisse said Chad's capacity to absorb new arrivals was severely overstretched, with the country already hosting 1.3 million refugees, including 794,000 arrivals from Sudan since the conflict erupted two years ago.
"Humanitarian resources across the country remain extremely limited, while needs continue to grow for water, shelter, health, education and protection," he said.
The UNHCR said it needed $409 million to respond to the refugee crisis in Chad this year, but only 20 percent of that had been funded to date.
There were no immediate reports of any casualties from the shelling, which followed a similar bombardment of the army's General Command headquarters in Khartoum on April 26.
