RAF transport planes have taken part in an air drop to bring urgently needed humanitarian aid to the besieged Iraqi town of Amirli, Defence Secretary Michael Fallon said.
The Hercules aircraft formed part of an international effort to resupply the town which has been under siege by Islamic State (IS) militants for nearly two months.
Air strikes by United States warplanes against IS targets supported the relief effort, the Pentagon said, but Mr Fallon said the UK had not been asked to participate in military action.
Mr Fallon told Sky News' Murnaghan programme: "We have not been asked to participate either in sending troops on the ground or in joining in air strikes.
"But let me be clear what we have been doing.
"We have been putting in humanitarian aid, I can confirm that last night I authorised two Hercules to participate in the big aid drop on Amirli, a town that's been under siege for nearly two months.
"The RAF dropped 14 tonnes of food and water there for a Shia population there that's been completely besieged."
Setting out the UK's role, Mr Fallon said the UK will "look at any further action the Iraqi government thinks will help" but ruled out deploying combat troops.
He said: "We have not been asked to participate in air strikes. We welcome what the Americans are doing. Of course we'll look at any further action the Iraqi government thinks will help.
"We have been involved in ferrying supplies of arms as well as non-lethal equipment from eastern European countries - the Peshmerga, the Kurdish forces, tend to use eastern European equipment and ammunition.
"We have been involved in transporting supplies and we will continue to look favourably on any requests to do that."
He said the UK was providing surveillance for the Americans, supporting Haider Abadi's efforts to form an inclusive government and co-ordinating international action against IS.
"We are all involved in this," he said. "Last night the relief operation for Amirli there were French, Australian, American and British aircraft involved together."
He added: "We are helping in the way that we can at the moment. We are helping with humanitarian aid, we are helping with surveillance, we are helping with counter-terrorism, we are supporting the Abadi government, we are helping internationally.
"We have not been asked to commit either combat troops on the ground - and we are not going to do that - we've not been asked to join in other air strikes."
International Development Secretary Justine Greening said : "The situation in northern Iraq remains deeply worrying, with thousands of Iraqi men, women and children suffering at the hands of Isil (IS) terrorists.
"The UK's humanitarian response has been swift and effective. When people depend on our support and protection to survive, we will continue to take action.
"The RAF has now successfully delivered much-needed food and drinking water to people trapped in the town of Amirli, surrounded by Isil fighters. We are standing by people in their time of need."