Britain is the latest country to acknowledge its participation in the airstrikes that reportedly killed 83 soldiers in the Syrian city of Dayr al-Zawr on Saturday.
The British Ministry of Defence (MoD) confirmed on Monday that UK drones participated in the airstrikes against a Syrian military airbase in Dayr al-Zawr.
The MoD also said it is cooperating with the US-led coalition to investigate the incident.
"We can confirm that the UK participated in the recent coalition airstrike in Syria, south of Dayr al-Zawr on Saturday and we are fully co-operating with the coalition investigation," an MoD spokesman said.
The so-called coalition has been conducting airstrikes in Syria since 2014 without any authorization from Damascus or a UN mandate.
The air raids by the US Air Force and its allies have already caused a war of words between Russia, Syria and the United States.
Russia and Syria accuse Washington of deliberately launching the strikes to help the Daesh (ISIL) terrorist group advance in the area.
The Syrian General Command referred to the incident as a “serious and blatant aggression” against the Syrian army, adding that it was also “conclusive evidence" that the US-led coalition is supporting Daesh militants.
Russia also blasted the attack, with Vitaly Churkin, Moscow’s ambassador to the UN, saying that the US airstrikes did not seem to be a mistake.
However, the White House has rejected the accusation, saying the air raids were unintentional.
Australia and Denmark have also announced their aircraft were among a group of Western warplanes that targeted the Syrian forces.
The attack is likely to endanger an already shaky ceasefire deal, which was agreed by the US and Russia and came into effect in Syria on Monday 12 September.