"We can confirm that the UK participated in the coalition air strike south of Deir Ezzor on Saturday, and we are fully co-operating with the coalition investigation," a defence ministry spokesman said.
"The UK would not intentionally target Syrian military units," the spokesman said.
Russia said the strikes killed 62 Syrian soldiers and injured around a hundred others, accusing the US of undermining a ceasefire deal struck in Geneva a week ago.
The Syrian Observatory for Human Rights monitor said the number of regime troops killed was at least 90.
Washington said coalition forces believed they were hitting a fighting position held by the Islamic State jihadist group but has also said it will investigate the incident.
Britain 's Press Association news agency reported that an unmanned Reaper drone may have been involved.
Australia earlier said it was one of several coalition countries whose aircraft took part and offered its "condolences to the families of any Syrian personnel killed or wounded".