More than 30,000 refugees from eastern Democratic Republic of Congo fleeing a rebel attack on the town of Kamango have arrived in neighbouring Uganda, UN officials said on Saturday.
Streams of refugees have crossed the border into western Uganda's Bundibugyo district since the attack on Thursday.
In Bundibugyo, refugees carried their belongings piled on their heads, including rolled up mattresses, cooking pots and chickens.
"We were woken in the darkness before dawn on Thursday by shooting, gunshots," said one mother of three, who declined to give her name.
"I just grabbed my children and what I could carry, and we ran towards Uganda, we were frightened of being killed."
An AFP photographer said that long lines of refugees were crossing a border bridge into Uganda every hour.
Some were returning back into Congo to try to retrieve more of their belongings and livestock, but said they would then come back to safety in Uganda, they said.
United Nations refugee agency official Karen Ringuette said that more than 30,000 had entered Uganda.
Richard Nsubuga, from the Ugandan Red Cross, said they were working hard to support the thousands arriving, with refugees putting up makeshift tents in the grounds of a school.
"People are sleeping in the open air, because the classrooms now are full of people sheltering there," he said.
The town of Kamango in the northernmost part of North Kivu province was attacked and briefly occupied Thursday by a Ugandan-led rebel group, the Allied Democratic Forces (ADF).
Residents of Kamango said that public buildings and the hospital had been pillaged but no toll was given of possible casualties.
Ugandan army spokesman Paddy Ankunda said on Saturday that troops had been sent to reinforce positions along the border with Congo.
"We have deployed enough forces on our common border to ensure these terrorists (ADF) do not cross the line, because Uganda is their target," Ankunda said.
"We are in contact with the Congolese army and the situation is getting back to normal, but people have continued to enter Uganda fearing the rebels will kill them."
The ADF was formed in the mid-1990s in the Rwenzori mountains in western Uganda, close to the DR Congo border.
Part of the ADF is now based in DR Congo after Ugandan government forces attacked their bases two years ago.
It has been relatively quiet in recent years, and it was not immediately clear what sparked the ADF to attack Kamango.