Iraqi army launch a rocket towards Islamic State militants during a battle with Islamic State militants near Ghozlani military complex, south of Mosul, Iraq February 23, 2017. REUTERS/Alaa Al-Marjani

WASHINGTON (Reuters) - Four civilians were killed in February by U.S.-led coalition forces in Iraq and Syria, the U.S. military said on Saturday as it updated a tally of accidental deaths in the fight against the Islamic State militants.

At least 229 civilians have been unintentionally killed by air strikes since the U.S.-led operation against the militants began almost three years ago, the Pentagon said in a statement.

The official tally of civilian deaths since this campaign started is far lower than what outside groups report for that period. Coalition air strikes have killed more than 2,800 civilians, according to monitoring group Airwars.

As many as 200 people were buried by rubble after a coalition air strike in Mosul in mid-March, witnesses said.

The Pentagon has said it is investigating that incident and several dozen more reported cases of civilian deaths in the last two years.

“We regret the unintentional loss of civilian lives ... and express our deepest sympathies to the families and others affected by these strikes,” the Pentagon statement said.

Included in Saturday’s tally of 229 deaths were four civilians killed in a September 2015 strike near Mosul, the military said, as well as one civilian killed in January of this year in a strike on an Islamic State weapons facility near Mosul.

Also on Saturday, Iraqi state TV said Ayad al-Jumaili, believed to be the deputy of Islamic State leader Abu Bakr al-Baghdadi, has been killed in an air strike, citing Iraqi military intelligence.