Sixty-four civilians were killed and eight injured in 24 US airstrikes against Islamic State targets in Iraq and Syria between 20 November 2015 and 10 September 2016, the US military said in a statement on Wednesday.

“In each of the cases released today, the assessment determined that although all feasible precautions were taken and strikes complied with laws of armed conflict, civilian casualties unfortunately did occur,” Colonel John Thomas, a spokesman for US Central Command, said in a statement.

In a strike on 20 November, five civilians were killed near Dayr Az Zawr, Syria after they entered the target area after the aircraft released its weapons.

In a strike on 5 March, near Mosul, Iraq, 10 civilians were killed in a strike against an Islamic State “weapons production facility”, the statement said.

“Mitigating civilian casualties is a key component of the counter-Isil air campaign, and we’ve applied lessons learned to reduce the likelihood of future civilian casualties,” Thomas said, using an acronym for Islamic State.

Including the latest disclosure, the Pentagon has assessed that 119 civilians have been killed in US airstrikes since 2014, while 37 have been injured, Major Josh Jacques, another spokesman for US Central Command, said.

Last month a report from Amnesty International said that about 300 civilians have been killed in 11 coalition attacks in the past two years.

Jacques said the latest release did not include an investigation into a coalition air strike in mid-July near Manbij, Syria, which groups say killed dozens of civilians, but that it was near completion.

The United States has conducted 12,354 air strikes against Islamic State as of 2 November, with 6,992 in Iraq and 5,362 in Syria, according to US military data.

The operation against Islamic State in Iraq and Syria has cost $9.3bn since 2014, the data shows.