(CNN) -- A government airstrike misfired on a refugee camp in Yemen killed dozens of civilians, officials from the government and humanitarian agencies said.
Thursday's strike was meant to target Shiite rebels, according to the government officials, who spoke on condition of anonymity. Houthi Shiite rebels were fighting near the site, the officials said.
The government officials put the death toll at 86, while the U.N. Children's Fund said "reliable" government and media sources put the death toll at 87.
CNN could not independently verify those numbers, and the Yemeni government did not officially comment on the airstrike.
According to reporters from the Yemen Post who were on ground near the strike, regional tribes that support the government in the fight against the Shiite rebels withdrew from combat to protest the airstrike.
The U.N. Children's Fund on Thursday decried the high number of civilian casualties in the airstrike without specifying how many had died.
"UNICEF is deeply concerned about reports that civilians, including children, died in an air raid on a camp for displaced persons in northern Yemen," the statement said.
"This latest incident is a tragic development in an already alarming situation. More than a month after the latest escalation of fighting, children affected by the conflict still have no access to safe water, adequate sanitation, health care and protection."
The United Nations recently said fighting between government forces and Houthi Shiite rebels in northern Yemen has displaced 150,000 people.
Battles between Yemeni forces and rebels in the north have raged intermittently for five years. A government offensive launched last month has escalated bloodshed.
The conflict is considered to be both separatist -- over who will assert authority in the area -- and sectarian -- whether Shiite Islam will dominate in majority Sunni Yemen. The rebels are supporters of slain Shiite cleric Hussein al-Houthi.