Syria crisis: 'Children died' in US air strike
A US air strike on Syria last year probably killed two children, officials say - the first admission of civilian casualties in the campaign.
"We regret the unintentional loss of lives," said Lieutenant General James Terry, head of the US-led campaign.
US Central Command said the strike on 5-6 November, near Harim City, targeted the al-Qaeda-linked Khorasan Group.
There had been no indications prior to the strikes that children were present, officials said.
The admission followed an investigation into the incident by US military authorities, directed by Lt Gen Terry.
A statement on the investigation said the Pentagon conducted a "thorough assessment, review and validation process" and concluded the target buildings were being used exclusively for military purposes.
Two "non-combatant" adults also received minor injuries in the strike, which targeted an explosives manufacturing facility, the statement said.
"The coalition continues to take all reasonable measures during the targeting process to mitigate risks to non-combatants and to comply with the principles of the Law of Armed Conflict," Lt Gen Terry said.
Civilian death toll
Thursday's statement is the first US acknowledgment of civilian casualties caused by the air campaign, despite a UK-based activist group documenting more than 100 deaths.
The Syrian Observatory for Human Rights (SOHR) said on Wednesday that 131 civilians had been killed in coalition air strikes since September, including 42 children.
A single strike on the northern Syrian province of Aleppo was said by the group to have killed 52 civilians, seven of whom were children.
A spokesman for US Central Command said at the time it had "no information to corroborate" the claim but added: "We take all allegations seriously and will look into them further."
The SOHR said a total of 2,440 people had been killed by coalition air strikes, the vast majority of them Islamic State militants.
US military officials have examined 46 separate reports of civilian casualties caused by the air campaign since 8 August, according to a Pentagon spokeswoman.
Of those, 35 were found to be either not credible or there was not enough information to assess them, she said.
Three of the allegations, involving three separate incidents, are being investigated and the credibility of six other allegations is still being assessed, she added.
Relatively little is known about the Khorasan group other than information released by US officials.
They say the group is made up of veteran fighters from the Afghanistan and Pakistan region who have embedded themselves within al-Qaeda's Syria branch, the al-Nusra Front.
The US Air Force began striking Islamic State linked targets in Syria in September, leading a coalition including Bahrain, Jordan, Qatar, Saudi Arabia, and the United Arab Emirates.
The UK and other European countries have participated in air strikes against targets in Iraq only.